10. What is the measure of angle C?
A. 25°
B. 30°
C. 60°
D. 75°
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Answer:
D
Step-by-step explanation:
x + 5 + 3x + C = 180 All triangles have 180 degrees.
4x + 5 + C = 180
But C must be equal to 3x. Notice the markings on the lets of the triangle.
4x + 5 + 3x = 180
7x + 5 = 180 Subtract 5 from both sides
7x = 180 - 5
7x = 175
x = 25
But angle C = 3x
C = 3*25
C = 75