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A. 86
B. 111
C. 69
D. 71

A. 86 B. 111 C. 69 D. 71-example-1
User Alex Ngo
by
5.6k points

2 Answers

3 votes
All the angles of a triangle add up to 180 degrees.

30+39+<4= 180

69+<4= 180

Subtract 69 on both sides.

<4= 111 degrees

<1 and <4 are supplementary and adjacent. They equal 180 degrees as well.

111+<1= 180

<1= 69 degrees

I hope this helps!
~kaikers
User Xman Classical
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5.4k points
4 votes
M∠2 = 39, M∠3 = 30

M∠4 = 180 - (M∠2 + M∠3)
M∠4 = 180 - (39 + 30)
M∠4 = 180 - 69
M∠4 = 111

180 - M∠4 = M∠1
180 - 111 = M∠1
M∠1 = 69

M∠1 = 69

C is your answer


hope this helps
User BRBdot
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5.7k points