Question

find the area of base and radius of a cylinder if it's curved surface area is 660sq.cm and height is 21 cm.​

Answer 1

Given:

✰ Curved surface area = 660 cm²

✰ Height of a cylinder = 21 cm

To find:

✠ The area of base of a cylinder.

✠ The radius of a cylinder.

Solution:

As we are provided with the curved surface area and height of a cylinder, we will first calculate its radius by using formula of curved surface area putting the values in the formula and then doing the required calculations. After that we will calculate the area of the base of a cylinder by using its formula.

Let's find out...✧

✭ Curved surface area = 2πrh ✭

Where,

• r is the radius of the cylinder.
• h is the height of the cylinder.

Putting the values in the formula, we have:

➛ 660 = 2 × 22/7 × r × 21

➛ 660 = 44/7 × r × 21

➛ 660 = 44 × r × 3

➛ r = 660/(44 × 3)

➛ r = 220/44

➛ r = 5 cm

∴ The radius of a cylinder = 5 cm

Now, find out the base area.

✭ Area of base of a cylinder = πr² ✭

➛ Area of base of a cylinder = 22/7 × 5²

➛ Area of base of a cylinder = 22/7 × 25

➛ Area of base of a cylinder = 550/7

➛ Area of base of a cylinder ≈ 78.57 cm²

∴ The area of base of a cylinder ≈ 78.57 cm²

_______________________________

Answer 2

Answer:

Given:

✰ Curved surface area = 660 cm²

✰ Height of a cylinder = 21 cm

To find:

✠ The area of base of a cylinder.

✠ The radius of a cylinder.

Solution:

As we are provided with the curved surface area and height of a cylinder, we will first calculate its radius by using formula of curved surface area putting the values in the formula and then doing the required calculations. After that we will calculate the area of the base of a cylinder by using its formula.

Let's find out...✧

✭ Curved surface area = 2πrh ✭

Where,

r is the radius of the cylinder.

h is the height of the cylinder.

Putting the values in the formula, we have:

➛ 660 = 2 × 22/7 × r × 21

➛ 660 = 44/7 × r × 21

➛ 660 = 44 × r × 3

➛ r = 660/(44 × 3)

➛ r = 220/44

➛ r = 5 cm

∴ The radius of a cylinder = 5 cm

Now, find out the base area.

✭ Area of base of a cylinder = πr² ✭

➛ Area of base of a cylinder = 22/7 × 5²

➛ Area of base of a cylinder = 22/7 × 25

➛ Area of base of a cylinder = 550/7

➛ Area of base of a cylinder ≈ 78.57 cm²

∴ The area of base of a cylinder ≈ 78.57 cm²

_______________________________

Explanation:

Hope this answer will help you.