There is a formula to the area of a trapezoid. the (top base+bottom base)* height/2
But we need to find the height. we can cut and make a triangle and a square.
to find the height, we know the triangle has a base of 14-8=6
6^2+x^2=10^2
36+x^2=100
x^2=64
x=8
Since we now know the height, we can plug it in the equation
(8+14)8/2
88 is the area of the trapezoid