Question

1. challenge: find the value of x.

(2x)°
90°
(5x + 8)°
x =

Explanation:

Step1: Sum triangle angles to 180°

$$(2x+5) + 90 + (5x+8) = 180$$

Step2: Combine like terms

$$7x + 103 = 180$$

Step3: Isolate the x-term

$$7x = 180 - 103$$
$$7x = 77$$

Step4: Solve for x

$$x = \frac{77}{7}$$

Answer:

$x = 11$