Tolong di bantu kak​

A^2 + b^2 = c^2
(1/2 AB)^2 + t^2 = AC^2
(1/2 x 18)^2 + t^2 = 15^2
9^2 + t^2 = 15^2
81 + t^2 = 225
t^2 = 225 – 81
t^2 = 144
t segitiga = 12 cm

L permukaan prisma segitiga
= (2 x L alas) + (K alas x t prisma)
= (2 x 1/2 x a x t segitiga) + (jumlah sisi segitiga x t prisma)
= (2 x 1/2 x 18 x 12) + {(15+15+18) x 25}
= 216 + (48 x 25)
= 216 + 1.200
= 1.416 cm^2 (B)