What is the measurement of ∠y?

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What is the measurement of ∠y?
A. 60
B. 65
C. 70
D. 75
E. 80

*An answer will be posted in 2 days.
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by OptimusPrep » Thu May 19, 2016 4:07 am
Max@Math Revolution wrote:What is the measurement of ∠y?
A. 60
B. 65
C. 70
D. 75
E. 80

*An answer will be posted in 2 days.
Angles of the top most triangle = 40, 180 - 2x, 180 - 2k
Sum of the angles of a triangle = 180

Therefore,

40 + 180 - 2x + 180 - 2k = 180
k + x = 110 - (i)

Coming to the lower triangle,
Sum of angles:
x + k + y = 180

From (i), we know that x + k = 110,
Hence y = 180 - 110 = 70

Correct Option: C

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by Max@Math Revolution » Sun May 22, 2016 4:29 pm
From (180-2k)+(180-2x)+40=180, we get 220-2(x+k)=0, 2(x+k)=220, x+k=110. Since X+k+y=180, if we substitute, from 110+y=180, we know y=70. Hence, the correct answer is C.

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by bubai800 » Mon May 23, 2016 1:09 am
70 degree