Me solve and show all steps and you

Since opposite angles in a trapezoid are supplementary (add to 180) we can say that :

x + 2x =180
3x = 180
x=60

So, angle A = 120 ° and angle C = 60°

Okay. So m<A=120 m<B=120 m<C= 60 m<D = 60 :D

Work:

opposite angles add up to 180 if it's an isosceles trapezoid. 
So you do 2x+x=180
3x=180
x=60
Then you plug it in. 
2(60)= 120
(60)=60
and the top two angles are always congruent in an isosceles trapezoid, and the bottom two too. 
so m<A=120 m<B=120 m<C= 60 m<D = 60 

X= 2 he can buy 2 packs of cards for $12 and an action figure for $3 so he would spend $15 in total plus the free poster