Question

∠C and ∠D are complementary.

Let m∠C=(5x)° and m∠D=(7x−6)°.

What is the value of x?

Enter your answer in the box.

x =

Answer 1

Complementary angles have sum 90°

`\\ \rm\Rrightarrow 5x+7x-6=90`

`\\ \rm\Rrightarrow 12x-6=90`

`\\ \rm\Rrightarrow 12x=96`

`\\ \rm\Rrightarrow x=8`

Answer 2

x = 8

Explanation:

Complementary angles are two angles with measures that sum to 90°

Given:

• m∠C = (5x)°
• m∠D = (7x − 6)°

⇒ m∠C + m∠D = 90°

⇒ 5x + 7x - 6 = 90

⇒ 12x - 6 = 90

⇒ 12x = 96

⇒ x = 8