Как доказать подобность треугольников АДБ и АВС, если отрезок АД является перпендикуляром к отрезку
Как доказать подобность треугольников АДБ и АВС, если отрезок АД является перпендикуляром к отрезку ВС и перпендикуляром к отрезку АВ?
19.12.2023 00:39
To prove the similarity of triangles ADB and ABC, we need to show that their corresponding angles are equal and their corresponding sides are proportional.
Explanation:
1. We know that AD is perpendicular to BC and AB. This means that angle ADB is a right angle and angle ABC is a right angle.
Angle ADB = 90 degrees and angle ABC = 90 degrees.
2. Since both triangles have one right angle, they also have a common angle A. So, we have angle A = angle A.
3. Now, let"s consider the side lengths. We have segment AD and segment AB, which are perpendicular to each other.
4. Using the Pythagorean theorem, in triangle ADB, we have the relation AD^2 + DB^2 = AB^2.
5. In triangle ABC, we have the relation AC^2 = AB^2 + BC^2.
6. Since AB^2 is common to both triangles, we can rewrite the equations as AD^2 + DB^2 = AC^2.
7. From the above equation, we can see that the squares of the corresponding sides of triangles ADB and ABC are proportional. Hence, the triangles are similar.
Example of use:
Given: AD = 6 cm, DB = 8 cm, AC = 10 cm.
To prove: Triangle ADB ~ Triangle ABC.
Proof:
1. Angle ADB = 90 degrees and angle ABC = 90 degrees.
2. Angle A = angle A.
3. AD^2 + DB^2 = 6^2 + 8^2 = 100 = AC^2.
4. Since the squares of the corresponding sides are proportional, we can conclude that triangles ADB and ABC are similar.
Advice:
To understand the concept of proving triangle similarity, it is important to have an understanding of basic geometric principles such as right angles, Pythagorean theorem, and proportionality of sides.
Exercise:
Given triangle XYZ, where angle Y = 90 degrees and angle X = 30 degrees. Side XY measures 5 cm. Find the value of side YZ.