Area of trapezoid:
A = 1/2(b1+b2)h
where
b1 = 30,
b2 = 28+12 = 40
Triangle FOG
a^2 = c^2 - b^2
a^2 = 13^2 - 12^2
a^2 = 169 - 144
a^2 = 25
a = √25
a = 5
FO = 5 so height h = FO = 5
Now you can find the Area of trapezoid
A = 1/2(b1+b2)h
A = 1/2(30 + 40) (5)
A = 1/2(70)(5)
A = 175
Answer
175 square units