A sheet metal roof in the shape of a right triangular prism needs painting on its top and lateral surfaces only. Base triangle has sides 6, 8, 10 cm and prism length is 12 cm. Find the painted area.
Show answer & explanation
Correct answer: C
Explanation
Given:
Base triangle sides = 6 cm, 8 cm, 10 cm
Prism length = 12 cm
Area of top triangular face
= (1/2) × Base × Height
= (1/2) × 6 × 8
= 24 cm²
Lateral Surface Area (LSA)
= (Perimeter of base) × Length
= (6 + 8 + 10) × 12
= 24 × 12
= 288 cm²
Total painted area
= Top area + LSA
= 24 + 288
= 312 cm²
Correct Answer: 312 cm² (Option 3)