Angle ADE = 90.

CD=BE=5

AE=5

∴s△ADE=3*4*0.5=6

S parallelogram DEBC=DC* height

Height *AE=3*4 (area of triangle)

Height =2.4

S parallelogram DEBC=DC* height = 12.

So the area of trapezoidal ABCD is 12+6= 18.