Question

What are the measures of angles B and C?

O ZB = 15°; ZC = 165°
O ZB = 65°; ZC = 115°
O ZB = 65°; ZC = 65°
O ZB = 15°; ZC = 15°

Answer 1

B. m<B = 65°; m<C = 115°

Explanation:

First find the value of x:

3n + 20 = 6n - 25 (opposite bangles if a parallelogram are equal)

Collect like terms

3n - 6n = -20 - 25

-3n = -45

Divide both sides by -3

n = 15

✔️Find angle B:

m<B = 3n + 20

Plug in the value of n

m<B = 3(15) + 20

m<B = 45 + 20

m<B = 65°

✔️Find angle C:

m<C = 180 - m<B (consecutive angles of a parallelogram are supplementary)

m<C = 180 - 65

m<C = 115°