Calculate the shaded area of the figure

Ibaratkan :
segitiga besar = a
segitiga kecil = b

Diketahui :
panjang alas a = 62 cm
panjang alas b = 62 cm
tinggi a = 30 cm
tinggi b = 21 cm

Jawab :
Luas arsiran = (luas a)-(luas b)
L = (62 x 30/2) - (62 x 21/2)
L = (1860/2) - (1302/2)
L = 930 - 651
L = 279 cm^2 

Maaf jika ad kesalahan :)