Question

find the C.S.A and T.S.A and volume of cone whose radius is 21cm and height is 28 cms​

Answer 1

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Answer 2

Answer:

• CSA of cone = 2310 cm²
• TSA of cone = 3696 cm²
• Volume of cone = 12936 cm³

Step-by-step explanation:

Given:

• Radius of cone = 21 cm
• Height of cone = 28 cm

To Find:

• Curved Surface area of cone (CSA).
• Total Surface area of cone (TSA).
• Volume of cone.

Now, first we will calculate Slant height (l) of cone.

We know that,

=> Slant Height (l) = √r² + h²

=> Slant Height (l) = √(21)² + (28)²

=> Slant Height (l) = √441 + 784

=> Slant Height (l) = √1225

=> Slant Height (l) = 35 cm

Hence, Slant Height (l) of cone = 35 cm.

___________________________

Now, we will calculate CSA of cone,

=> CSA of cone = πrl

=> CSA of cone = (22/7) × 21 × 35

=> CSA of cone = 16170/7

=> CSA of cone = 2310 cm²

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Now, we will calculate TSA of cone,

=> TSA of cone = πrl + πr²

=> TSA of cone = 2310 + (22/7) × 21 × 21

=> TSA of cone = 2310 + 22 × 3 × 21

=> TSA of cone = 2310 + 1386

=> TSA of cone = 3696 cm²

____________________________

Now, we will calculate Volume of cone,

=> Volume of cone = 1/3 πr²h

=> Volume of cone = 1/3 × 22/7 × 21 × 21 × 28

=> Volume of cone = 22 × 21 × 28

=> Volume of cone = 12936 cm³