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The base of a solid right prism is a triangle whose sides are 9 cm, 12 cm and 15 cm. The height of the prism is 5 cm. Then, the total surface area of the prism is
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- 180 cm²
- 234 cm²
- 288 cm²
- 270 cm²
- 180 cm²
Correct Option: C
Perimeter of triangle
| S = | = 18 cm | |
| 2 |
∴ Area of triangle = √s (s - a)(s - b)(s - c)
= √18(18 - 9)(18 - 12)(18 - 15)
= √18 × 9 × 6 × 3 = 54 sq.cm.
∴ Total surface area of the prism = Perimeter of base × height + 2 × Area of base
= 36 × 5 + 2 × 54 = 288 sq.cm.
