Diketahui trapesium siku-siku ABCD, Siku-Siku di A, AB//CD,BC=Diagonal, AC=15 cm,CD=9 cm ; AB=18 cm. Luas trapesium ABCD adalah? a. 164cm persegi (cm pangkat2)

TRAPESIUM SIKU-SIKU ABCD
Siku-siku di A
AB//CD
BC = Diagonal = AC = 15 cm
CD = 9 cm
AB = 18 cm
L = ...???
t^2 = AC^2 - (1/2 × AB)^2
t^2 = 15^2 - (1/2 × 18)^2
t^2 = 15^2 - 9^2
t^2 = 225 - 81
t^2 = 144
t = akar 144
t = 12 cm

L = 1/2 × (AB+ CD) × t
L = 1/2 × (18 + 9) × 12
L = 1/2 × 27 × 12
L = 162 cm^2 (b)