Question

Find these degrees
m m

Answer 1

x = 14

Explanation:

m∠B and m∠D are congruent angles, which means they are equal in measurement.

We can write the following equation to find the value of x:

5x - 7 = 3x + 21

• Transfer like terms to the same side of the equation

5x - 3x = 21 + 7

• Add/subtract like terms

2x = 28

• Divide both sides by 2

x = 14

To find the measure of m∠B, replace x with 14:

5 × 14 - 7 = 63°

• m∠B and m∠C are supplementary angles, so we can find the measure of m∠C using this information:

63 + m∠C = 180

• Subtract 63 from both sides

m∠C = 117°