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The base of a right pyramid is an equilateral triangle of side 4 cm each. Each slant edge is 5 cm long. The volume of the pyramid is
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4√8 cm³ 3
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4√60 cm³ 3
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4√59 cm³ 3 -
4√61 cm³ 3 - None of these
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Correct Option: E
Area of the base of pyramid = | × (side)² | |
4 |
= | × 4 × 4 = 4√3sq.cm. | |
4 |
Length of median on the base (AD) = √4² - 2²= √12
= 2√3 cm
∴ OD = | × 2√3 = | cm. | ||
3 | √3 |
Height of pyramid = √5² - | ² | |||
√3 |
Height of pyramid = √25 - | = | cm | ||
3 | √3 |
∴ Volume of pyramid = | × area of base × height | |
3 |
∴ Volume of pyramid = | × area of base × height | |
3 |
= | cu.cm. | |
3 |