12. If ABCD is a parallelogram, find mzC.
A
B
(5x + 38)
(8x - 19°
С
D
A
B
(5x + 38)
(8x - 19°
С
D
Answer:
85°
Step-by-step explanation:
m<B = m<D (opposite angles of a parallelogram)
Therefore:
5x + 38 = 8x - 19
Collect like terms.
5x - 8x = -38 - 19
-3x = -57
Divide both sides by -3
x = 19
m<C + m<B = 180° (consecutive angles of a parallelogram are supplementary)
(5x + 38) + m<C = 180°
Plug in the value of x
5(19) + m<C = 180°
m<C = 180 - 95
m<C = 85°
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