Question 1011972
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Triangle ABC is isosceles, with angle CAB=angle ACB.
Triangle ADC is isosceles with angle CAD=angle CDA.
Given angle CDA=75 degrees, angles CAB (∠A) and ACB (∠C) also equal 75 degrees.
Angles CAB (∠A), and CBA (∠B), ACB (∠C) form the triangle ABC, 
thus their sum is 180 degrees:
∠A + ∠B + ∠C = 180 degrees
75 degrees  + ∠B + 75 degrees = 180 degrees
∠B = 30 degrees
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ANSWER The measure of Angle B is 30 degrees.
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