Question

Use what you know about triangles and angle relationships to determine the value of x and y in this isosceles triangle.

(Note: use whole numbers only, do not type the degree
symbol or the word)

Answer 1

x = 13

y = 7

Explanation:

✔️Recall that sum of the interior angles of a ∆ = 180°

Therefore:

(3x - 3) + (4x + 20) + (7x - 19) = 180° (sum of ∆)

Solve for x

3x - 3 + 4x + 20 + 7x - 19 = 180

14x - 2 = 180

Add 2 to both sides

14x = 182

Divide both sides by 14

✅x = 13

✔️Recall also that an isosceles has two equal sides, therefore:

8y - 7 = 5x - 16

Plug in the value of x

8y - 7 = 5(13) - 16

8y - 7 = 65 - 16

8y - 7 = 49

Add 7 to both sides

8y = 56

Divide both sides by 8

✍️y = 7