Question

the csa of rt. circular cone is 490cm2 and radius of base is 20cm find its l and tsa

Answer 1

Answer:

CSA of Right circular cone = πrl

We are given with values:

• r = 20 cm

• πrl = 490 cm²

Taking π as 3.14 we get,

⇒ 3.14 × 20 × l = 490

⇒ l = 490 / 20 × 3.14

⇒ l = 490 / 62.8 = 7.80 cm

TSA of cone = πrl + πr²

πrl is already given as 490 cm².

So, πr² is 3.14 × ( 20 )² which is 1256 cm²

⇒ TSA of cone = 490 + 1256 = 1746 cm²

This is the required answer.