i don't know the answer to this question, but i can give you an example that way you can find your own answer!
possible answers for the example question:
65∘
115∘
35∘
75∘
85∘
To find the measure of angle DAC, we must know that the interior angles of all triangles sum up to 180 degrees. Also, as this is an isosceles trapezoid, ∠ADC and ∠BCD are equal to each other. The two diagonals within the trapezoid bisect angles ∠ADC and ∠BCD at the same angle.
Thus, ∠ACD must also be equal to 50 degrees.
Thus, ∠ADC=50+15=65.
Now that we know two angles out of the three in the triangle on the left, we can subtract them from 180 degrees to find ∠DAC:
180−65−50=65
the correct answer for the example question is 65 degrees
