The volume of a right circular cone is 924 cm3. If its height is 18 cm, then the area of its base (in cm) is:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e 154
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Concept |
Application |
Fair calculation |
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Volume of a cone: 1/3 π r2h |
V = 1/3 π r2h ⇒ 924 = 1/3 × 22/7 × r2 × 18 ⇒ r2 = 49 ⇒ r = 7 cm Hence, Area of base = π r2 = 22/7 × 49 = 154 cm2 |
924 = 1/3 × 22/7 × r2 × 18 ⇒ 924/6 = 22/7 × r2 ⇒ 42/6 = 1/7 × r2 ⇒ r2 = 7 × 7 ⇒ r = 7
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