The isosceles trapezoid abde is part of an isosceles triangle ace. find the measure of the vertex angle of ace. (see attachment)

a. 130 degrees

b. 60 degrees

c. 65 degrees

d. 50 degrees

i really need an explanation along with the answer,

We know that is isosceles, that means , by definition.

Also, , because .

Then, we have , by sumpplementary angles.

Which means,

, by definition.

Then,

Therefore, the measures of vertex angles are 65 for the base angles of triangle and 50 for the different angle.

-3.5 is the distance.

i've had this question so choose the one in the absolute value sign.