Drive the RV back to Datang

Chapter 304 Chapter 314: Li Tai's Promise

It seems that for the sake of face, Ge Erdongzan is going to hold on to the end, and he is determined not to ask Li Hao for an answer. If he wants an answer, he will think about it after returning to Tibet, but he will not believe it. With his own intelligence, as long as he is given enough time , will not be able to think of a way to solve this problem.

At this time, Li Tai on the side suddenly scratched his head frantically and yelled anxiously. Everyone was startled and turned their heads to look at Li Tai. Li Hao saw Li Tai's appearance and knew that he He was forced into this by the question he asked just now, no wonder he didn't ask for the answer just now, because he has been thinking about the problem all the time, it's really a matter of forgetting me.

"Li Hao! What's the answer!" Li Tai finally stopped scratching his head and screaming strangely, and then stared at Li Hao with wide eyes.

Li Hao was stunned when he heard the words, glanced at Li Tai, then turned to look at Lu Dongzan, Lu Dongzan sneered, as if to say: "I didn't ask this."

Li Hao thought for a while, then finally shook his head and said, "This question was asked by the Tubo Prime Minister. Only when the Tubo Prime Minister asks for help can I give the answer."

"What!" Li Tai was stunned for a moment when he heard the words, and immediately came to Lu Dongzan, saluting, "Senior Prime Minister, in order to understand the confusion in the junior's heart, please help the junior and ask Li Hao for the answer."

Lu Dongzan cupped his hands to return the salute, and shook his head apologetically, "His Royal Highness the King of Wei spoke seriously, please forgive Ge Erdongzan for being difficult to obey."

Li Tai was disappointed when he heard the words, and just about to turn his head and walk back, he suddenly had a flash of inspiration, and suddenly bent down to Lu Dongzan's ear and whispered: "As long as the prime minister can help me get the answer, I can help the prime minister." Marry a Tang princess and return home."

Lu Dongzan was shocked when he heard the words, looked at Li Tai with wide eyes in disbelief, and asked, "Is this true?"

"Of course it is true!" Li Tai replied solemnly.

Lu Dongzan believed that Li Tai is a dignified King of Wei, so he would not lie and deceive others, so he cupped his hands at Li Hao almost without hesitation: "Li County Marquis, please tell me the answer to that question just now."

Li Hao was slightly surprised when he heard the words. He didn't know what Li Tai said in Lu Dongzan's ear just now, which could change Lu Dongzan's attitude 180 degrees in an instant. But since Lu Dongzan asked the answer, he couldn't help but say it. He said, "Please return the pen to me."

Lu Dongzan returned the pen to Li Hao, and Li Hao turned his head to Li Shimin and said, "Your Majesty, I still want to ask for a ruler, but it's not an ordinary ruler, but a triangular ruler used by carpenters."

Li Shimin also wanted to know the answer, and immediately said loudly: "Come here, go to the Ministry of Industry and get a triangular ruler."

Immediately, Jin Wuwei took the order to go.

Everyone in the hall waited boredly, and Wei Wang Li Tai simply sat on the ground beside Li Hao and Lu Dongzan, waiting for the answer. He wanted to see Li Hao find out the point of opening a pier by the river with his own eyes.

After a long time, Jin Wuwei sent a triangular ruler out of breath. Li Hao took the triangular ruler and looked at it. He was very satisfied, and then began to explain the diagram.

Li Hao first coincided one right-angled side of the triangular ruler with the edge of the river, and then pushed it horizontally until the other right-angled side coincided with the Li's house, and then drew a dotted line along the right-angled side with a brush. This dotted line started from Li's house and followed the river The sides are connected and perpendicular to the river.

Li Tai hurriedly asked: "Is this the first way?"

"No." Li Hao shook his head and said, "This is an auxiliary line to help solve problems."

Although Li Tai had never heard of the term auxiliary line, once he heard the name and Li Hao's explanation, he immediately understood what an auxiliary line is.

Next, Li Hao extended the auxiliary line to the north, which was still a dotted line.

Lu Dongzan and Li Tai were beside him, watching Li Hao's drawing without blinking. Until now, they still don't understand why Li Hao draws this auxiliary line.

Then, Li Hao measured the length of the dotted line from Li's house to the south bank of the river. In fact, it was the shortest distance from Li's house to the river, which was exactly four inches. Therefore, he took the intersection of the dotted line and the south bank of the river as the starting point, and measured it in the northward direction of the dotted line. The length was four inches, and a big black dot was drawn on the four-inch part, and the text - "Muzi" was marked next to the black dot.

Seeing the black dot and the word "Muzi", Li Tai was full of doubts, but the point and route of the pier hadn't come out yet, so he could only endure it and wait for Li Hao to continue solving the problem.

Next, with the help of a ruler, Li Hao connected the black dot of "Muzi" and the circle of the Wang family into a line. At the intersection of this line and the south bank of the river, Li Hao wrote two words - "Dock"!
Li Tai and Lu Dongzan were shocked when they saw it, and the pier came out!

Li Hao drew a straight line between the pier point and Li's house. The pier and the two roads have all come out, and the problem solving is completed.

Li Hao picked up the drawn picture, showed it to everyone, and said loudly, "This is the correct answer."

Everyone stared wide-eyed. Although the pier points and two lines were drawn on the map, they still didn't understand the reasoning. Li Shimin coughed lightly and said, "Submit it here for me to see."

Xu Lian came to Li Hao, took the picture, and presented it to Li Shimin. Li Shimin stared at the picture for a long time, but couldn't see why.

Li Tai and Lu Dongzan were both frowning and thinking. They also felt that Li Hao's answer was correct, but they couldn't tell what the reason was. It was really painful like a cat's claws scratching their hearts.

After a while, Lu Dongzan couldn't bear it any longer, and asked, "Marquis Li, I think your answer is correct. Could you explain why you were looking for the pier just now?"

"Yes!" Li Tai also yelled anxiously, "Why did you draw an auxiliary line and a black dot called 'Muzi'?"

"Please stand up, both of you." Li Hao stood up slowly while speaking, Lu Dongzan and Li Tai also stood up.

Why did Li Hao call them to get up at this time, because... his feet are numb.

Li Hao lightly stomped on his numb right leg. After a while, he finally regained consciousness. Then he smiled awkwardly and said, "Actually, the key to solving this problem is 'between two points, the straight line is the shortest. '."

There is a most basic saying in geometry, which is called "the shortest line segment is between bright spots".Because in geometry, a straight line is infinitely long, so for the sake of scientific norms, it is said that the line segment is the shortest, not the straight line. However, people in this era do not know what a line segment is, and Li Hao is too lazy to explain to them what a line segment is. Say the straight line is the shortest.

Everyone nodded after hearing the words. Indeed, the straight line between two points is indeed the shortest.

Li Hao went on to say: "Think of the Li family and the Wang family as two points, and they cannot be directly connected, because the requirements are not met. The requirement is to set up a pier by the river, and the pier is also a point. Then There are only three points, how can the connection between these three points be the shortest, then, only these three points can be on a straight line.”

Li Tai and Lu Dongzan continued to nod. These principles seemed simple, but they didn't even think about it when they were thinking about the problem.

Li Hao continued to explain: "But you have also seen that Li's house and Wang's house are fixed points, and the dock is a movable point. However, although the dock can be moved, there are restrictions. It must be by the river, to be precise, on the south bank of the river. , with this heavy restriction, it is impossible for the pier to be on the same straight line as Li and Wang's family anyway, so we have to find a way to make these three points on the same straight line; just now King Wei asked me, why do we have to Draw a black dot called 'Muzi'. I don't know if you have noticed. Muzi's point and Li's point are actually symmetrical, and the axis of symmetry is the south bank line of the river. Your Majesty, please move the west side of the picture toward the up, with the east facing down, and show it to everyone."

According to Li Hao's words, Li Shimin flipped the picture, and suddenly, there was a low cry from the crowd. Sure enough, the dotted line between the two points of Li's house and Muzi was perpendicular to Henan, and it was as far from the south bank of the river as it was axially symmetrical.

Li Haodao: "This method is also called a mirror image. It is like a mirror reflecting things. Although the images are all virtual images, they are exactly the same size as the original object, but the direction is opposite, so Muzidian is actually the virtual image of the Li family on the north bank of the river, and the reason why such a virtual image is set up is to make the three points on the same straight line."

Li Tai and Lu Dongzan are both smart people. When they heard this, they finally realized it. After careful calculation, they found that the connection between Muzidian and the dock and the connection between Li’s house and the dock were also axisymmetric, that is to say, the length It's the same.

Many ministers still looked confused at this moment, expressing that they did not understand. Li Hao thought for a while, and suddenly said: "Your Majesty, please fold the paper along the line on the south bank of the river."

Li Shimin did as he said, the paper was very thin, when Li Shimin lifted it up, everyone exclaimed, only to see the picture inside the folded paper, and the two points of Li's family and Muzi overlapped in an instant , Now, the ministers finally understood.

Lu Dongzan had no choice but to give in this time, and he cupped his hands towards Li Hao and said, "Ge Erdongzan is far behind in the wisdom of Marquis Li County."

Li Hao bowed his hands and returned the salute, "Your Excellency is absurd. In fact, when I first saw this question, I never thought of an answer." When such a question came up, the whole class was stunned, and no one came up with the answer. Then the math teacher explained the method of solving the question, and finally told them a truth - "between two points, the line segment is the shortest".

"Okay." Li Shimin was very happy, blushing, "Since Li Hao, Marquis of Lantian County, won the battle of wits in front of the palace, I will marry Princess Wencheng to Li Hao, but Princess Wencheng is the daughter of the clan. , because I want to marry Tubo far away, I specially named the princess, and tomorrow I will issue a decree to remove the title of Princess Li Pingwencheng, the daughter of the clan, and give Li Hao a marriage, and choose a good day and auspicious day to get married!"

Lu Dongzan was slightly taken aback when he heard the words. It turned out that Princess Wencheng was not the emperor's daughter, but now he didn't care anymore, because he lost and couldn't help Songtsan Gampo marry Princess Wencheng back to Tibet. To marry a princess of the Tang Dynasty, one only needs to have the title of princess. Whether she is Li Shimin's daughter is not that important at all.

Lu Dongzan slowly turned his head to look at Li Tai, and said in a low voice, "His Royal Highness King Wei, don't forget your promise."

Li Hao on the side was taken aback when he heard the words: "Promise? What promise? What did Li Tai promise to him just now?"

Li Tai smiled lightly, and replied in a low voice: "This king will fulfill his promise now."

　Acknowledgment Thanks to the readers [npng], before and after Q reading, I rewarded about 19000 book coins, and today I went to the main site to reward 10000 book coins. This is an affirmation of Huajian’s books. Huajian is very happy, but Huajian is still the same sentence, read books rationally, and if you think it’s good, recommend the book to your friends to read together. You are a local tyrant, please ignore it, by the way, local tyrant, let’s be friends, (I raised my eyebrows, raised my eyebrows and smiled).

　　
　
(End of this chapter)