Question

6. Find the area of base and radius of a cylinder if its curved surface area is 990 sq cm and height is 15 cm.​

Answer 1

Given:-

• Curved surface area = 990 cm²
• Height = 15 cm

To Find:-

• Area of base
• Radius

Formula used:-

• CSA of Cylinder = 2πrh
• Area of circle = πr²

Solution:-

➨ CSA = 2πrh

➨ 990 = 2 × 3.14 × r × 15

➨ 990 = 94.2 × r

➨ r = 10.5095...

➨r = 10.5 cm

Now, Finding the area of base:-

➨ Area of base = πr²

➨ Area of base = 3.14 × (10.5)²

➨ Area of base = 346.185 cm²

Hence, the radius of the cylinder is 10.5 cm and the area of base is 346.185 cm².

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Answer 2

Given:

-curved surface area =990

-Hight =15

To find:

-Area of base

-radius

Formula used:

CSA of cylinder=2πrh

Area of circle=πr²

Solution:

-CSA=2πrh

990=2×3.14×r×15

990=94.2×r

r=10.5095

r=10.5cm

Now finding the area of base:

area of base =πr²

area of base =3.14×(10.5)^2

area of base=346.185cm^2

hence, the radius of the cylinder in 10.5 cm and the area of base is 346.185 cm^2