Respuesta :

AB = 36 cm
BC = 28 cm

Since they are similar figures:

36/28 = 9/EF

36EF = 28*9

EF = 252/36 = 7 cm

Finding the area:

Area = 1/2 * DE * EF

Area = 1/2 * 9 * 7

Area = 31.5 cm^2