05:Posttest
WCHS 2024 HS: Geometry [M] (Prescriptive) (GP)/ 5:Congruent Triangles: Part 2
4. In an A-frame house, the two congruent sides extend from the ground to form a 34° angle at the peak. What angle does each side form with the ground?

C
146°



Answer :

In this problem, we are dealing with an isosceles triangle formed by the two congruent sides of an A-frame house. Let's break down the solution step-by-step:

1. Understanding the Triangle:
- We have an isosceles triangle where the two congruent sides form an angle of 34° at the peak (the top vertex of the triangle).

2. Sum of Angles in a Triangle:
- The sum of all internal angles in any triangle is 180°.

3. Identifying the Known Angle:
- The angle at the peak of the triangle is given as 34°.

4. Calculating the Base Angles:
- Since the triangle is isosceles, the two angles at the base (i.e., where the sides meet the ground) are congruent.
- Let each of these base angles be represented as [tex]\( x \)[/tex].

5. Forming an Equation:
- We use the fact that the sum of the angles in a triangle is 180°:
[tex]\[ x + x + 34° = 180° \][/tex]
- Simplifying this equation:
[tex]\[ 2x + 34° = 180° \][/tex]

6. Solving for [tex]\( x \)[/tex]:
- Subtract 34° from both sides of the equation:
[tex]\[ 2x = 180° - 34° \][/tex]
- This simplifies to:
[tex]\[ 2x = 146° \][/tex]

7. Divide Both Sides by 2:
- To find [tex]\( x \)[/tex], divide 146° by 2:
[tex]\[ x = \frac{146°}{2} \][/tex]
- Thus, [tex]\( x = 73° \)[/tex].

Therefore, each side of the A-frame house forms a 73° angle with the ground. The angles are [tex]\( 34° \)[/tex] at the peak and [tex]\( 73° \)[/tex] at each base with the ground.