Question

the diameter of the base of a right circular cylinder is4.2 dm and its height is1 dm.find the area of the curved surface in cm square

Answer 1

✬ CSA = 1320 cm² ✬

Step-by-step explanation:

Given:

• Diameter of base of right circular cylinder is 4.2 dm.
• Height of cylinder is 1 dm.

To Find:

• What is the CSA of cylinder in cm² ?

Solution: First find the radius of cylinder.

➟ Radius = Diameter/2

➟ Radius = 4.2/2 dm

➟ R = 2.1 dm

[ Since, 1 dm = 10 cm ]

• Radius = 2.1(10) = 21 cm
• Height = 1(10) = 10 cm

As we know that

★ CSA of Cylinder = 2πrh ★

$\implies{\rm }$ CSA = 2(22/7)(21)(10)

$\implies{\rm }$ 44/7(210)

$\implies{\rm }$ 44(30)

$\implies{\rm }$ 1320 cm²

Hence, csa of right circular cylinder is 1320 cm².

Answer 2

Step-by-step explanation:

Given that, the diameter of the base of a right circular cylinder is4.2 dm and its height is1 dm.

We have to find the curved surface area of cylinder in cm².

Curved surface area of cylinder = 2πrh

From above data we have r is 2.1 dm (4.2/2) and h is 1 dm.

To convert dm into cm. Multiply the given value by 10. So, radius is 21 cm and height is 10 cm.

Substitute the values in above formula,

→ 2 × 22/7 × 21 × 10

→ 44 × 30

→ 1320

Hence, the curved surface area of the cylinder is 1320 cm².