tolong dibantu ya pakai cara:)

Ket:
Luas = L
Luas permukaan = LP

LP = 2(L AFB) + L ABCD + L ADEF + L FBCE
LP = 2(1/2 x 15 x 8) + (15 x 20) + (20 x 8) + (20 x FB)

Cari FB dulu menggunakan phytagoras:
FB = √15^2 + 8^2
FB =√225 + 64
FB = √289
FB = 17

maka:
LP = 2(1/2 x 15 x 8) + (15 x 20) + (20 x 8) + (20 x 17)
LP = 2(60) + 300 + 160 + 340
LP = 120 + 300 + 160 + 340
LP = 920

Jawaban: B.

Semoga membantu :)