In trapezoidal ABCD, ad is parallel to BC, AB is equal to 13cm, BC is equal to 18cm, CD is equal to 15cm, ad is equal to 4cm, find the area of s trapezoidal ABCD
Do am ⊥ BC through a and DN ⊥ BC through D
MN=AD=4
Let BM = x, CN = 14-x
AM²=169-x²
DN²=225-(14-x)²
AM =DN
x=5
AM ²=144、AM=12
Area = (4 + 18) × 12 △ 2 = 132