suatu prisma alasnya berbentuk segitiga dengan panjang sisi 3 cm , 4 cm , 5cm jika tinggi prisma segitiga adalah 9 cm berapa luas permukaan prisma?

LPp∆ = 2alas + s1 + s2 + s3

•alas = at/2
=> alas = 3×4/2 = 6 cm²

•s1 = p1 × tp
=> s1 = 3 × 9 = 27 cm²

•s2 = p2 × tp
=> s2 = 4 × 9 = 36 cm²

•s3 = p3 × tp
=> s3 = 5 × 9 = 45 cm²

LPp∆ = (2×6) + 27 + 36 + 45
=> LPp∆ = 12 + 108
=>LPp∆ = 120 cm²