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Please help! Geometry!

Please help! Geometry!-example-1
User Pezholio
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1 Answer

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Hello from MrBillDoesMath!

Answer: x - 90, y = 43

Discussion:

The triangles are congruent by the SAS theorem. (In left triangle, side = AB, angle = y; other side = AD). Because of congruence, angle ADC = x and (x + x = 180) as BDC is a straight line. So 2x = 180,or x = 90.

In the leftmost triangle : y + angle B + angle x = 180 as the sum of all angles in a plane triangle is 180 degrees. But angle B = angle C = 47 degrees as triangle ABC is isosceles. Putting this all together:

y + angle B + angle x = 180 =>

y + 47 + x = 180 =>

y + 47 + 90 = 180 =>

y + 137 = 180 =>

y = 180 - 137 = 43



Thank you,

MrB

User Yakup Ad
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