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Base of a right pyramid is a square whose area is 324 sq metre. If the volume of the pyramid is 1296 cu.metre, then the area (in sq. metre) of the slant surface is
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- 432
- 540
- 1080
- 360
- 432
Correct Option: B
| = | × area of base × height | |
| 3 |
| ⇒ 1296 = | × 324 × h | |
| 3 |
| ⇒ h = | 12 metre | |
| 324 |
∴ Side of square base = √324 = 18 metre
| ∴ Slant height = √12² + | > |  | ² | ||
| 2 |
= √12² + 9² = √144 + 81
= √225 = 15 metre
| ∴ Area of the lateral surfaces = | × perimeter of base × slant height | |
| 2 |
| = | × 4 × 18 × 15 | |
| 2 |
= 540 sq.metre.
