Question

2. The radius of the base of cone is 7 cm and its
vertical height is 15 cm. Find its volume and curved
surface area.​

Answer 1

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$\huge\red\bigstar$ GIVEN:

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•radius of cone is 7cm.

•vertical height is 15cm.

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$\huge\red\bigstar$ FIND:

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• volume of cone.

•CSA of cone.

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$\huge\red\bigstar$ formula used:

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•l²=r²+h²

•⅓πr²h

•πrl

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•according to first formula.

:$\implies$ l²=r²+h²

:$\implies$ l²=(7)²+(15)²

:$\implies$ l²=49 +225

:$\implies$ l²=274

:$\implies$ l=16.5cm

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• volume of cone =⅓πr²h

:$\implies$ ⅓ ×22/7×(5)²×15

:$\implies$ ⅓ ×22/7 ×25 ×15

:$\implies$ 5×22×3.57

:$\implies$ 392.7 cm³.

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volume of cone =392.7 cm³

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• curved surface area of cone = πrl

:$\implies$ 22/7 ×7 ×16.5

:$\implies$ 22×16.5

:$\implies$ 363cm².

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curved surface area of cone = 363cm².

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