Kk tolong jawab no 18 ,19 & 20 beserta jalan y kk tolong dibantu karna nanti pagi dikumpulin

18.
376/2 = 10x8 + 10t + 8t
188 = 80 + 18t
18t = 108
t = 108/18
t = 6 cm

V = 10 x 8 x 6 = 480 cm³

19.
V1 = 10x12x8 = 960 cm³
V2 = (10x3/2) x (12x3/2) x (8x3/2)
= 15x18x12
= 3.240 cm³
selisih = 3.240 - 960 = 2.280 cm³

20.
t = 0,6 x 10 = 6 cm
l = 12,5 cm
p = 14 cm

Lp = 2x(14x12,5 + 14x6 + 12,5x6)
= 2 x (175+84+75)
= 2 x 334
= 668 cm²