TLDR;
This video explains how the Pythagorean theorem is applied in real-life scenarios. It begins by emphasizing the importance of understanding the practical applications of theoretical knowledge. The video provides step-by-step instructions on how to solve word problems using the Pythagorean theorem, including drawing diagrams, inputting known measurements, applying the formula correctly, and answering the question. Several examples are provided, including calculating the height of a window, determining the height of a kite, finding the shortest distance traveled by a ship, and calculating the length of a cable needed to connect the top of a tower to a point on the ground.
- Real-world applications of the Pythagorean theorem.
- Step-by-step problem-solving approach.
- Practical examples with detailed explanations.
Introduction to Pythagorean Theorem in Real Life [0:00]
The video introduces the concept of applying the Pythagorean theorem to everyday situations, highlighting its relevance through examples such as architecture and carpentry. It emphasizes that understanding the practical applications of a theorem enhances its value. The presenter outlines the steps to solve word problems involving the Pythagorean theorem: creating a visual representation or sketch, labeling the known dimensions on the sketch, applying the Pythagorean theorem formula accurately, and providing an answer that directly addresses the question asked in the problem.
Example 1: Finding the Height of a Window [1:50]
The first example involves finding the height of a window using a ladder. A 5-meter ladder is placed 3 meters away from a wall, and the problem requires calculating the height the ladder reaches on the wall. The problem is solved by sketching a right triangle, where the ladder is the hypotenuse, the distance from the wall is one leg, and the height of the window is the other leg. Using the Pythagorean theorem, the height (t) is calculated as follows: t^2 = 5^2 - 3^2 = 25 - 9 = 16, so t = √16 = 4 meters. Thus, the height of the window from the ground is 4 meters.
Example 2: Determining the Height of a Kite [3:14]
In the second example, the height of a kite is determined. A child flies a kite with a 26-meter string. The horizontal distance from the child to the point directly under the kite is 24 meters. The task is to find the kite's height above the ground. The problem is visualized as a right triangle, with the kite string as the hypotenuse and the horizontal distance as one leg. The height (t) is calculated using the Pythagorean theorem: t^2 = 26^2 - 24^2 = 676 - 576 = 100, so t = √100 = 10 meters. Therefore, the kite's height above the ground is 10 meters.
Example 3: Calculating the Shortest Distance of a Ship [4:42]
The third example involves a ship sailing 100 km west and then 75 km south. The problem asks for the shortest distance from the ship's starting point. This forms a right triangle, where the westward and southward movements are the legs, and the shortest distance is the hypotenuse. The distance (C) is calculated as C^2 = 100^2 + 75^2 = 10,000 + 5,625 = 15,625, so C = √15,625 = 125 km. Alternatively, the problem is simplified using Pythagorean triples (3:4:5), recognizing that 75 and 100 are multiples of 25 (3x25 and 4x25), thus the hypotenuse is 5x25 = 125 km.
Example 4: Finding the Length of a Cable on a Tower [7:03]
The final example involves a 25-meter cable from the top of a tower to a point 7 meters from the base. The question is to find the length of a cable needed to reach a point 18 meters from the base. First, the height of the tower (FT) is found using the Pythagorean theorem: FT^2 = 25^2 - 7^2 = 625 - 49 = 576, so FT = √576 = 24 meters. Then, the length of the new cable (BT) is calculated using the tower's height and the new distance: BT^2 = 18^2 + 24^2 = 324 + 576 = 900, so BT = √900 = 30 meters. Thus, the length of the cable needed for the 18-meter distance is 30 meters.
