Question

A pipe 15m long and 20cm was painted on the outer side wall. How much area was painted in cm square

Answer 1

$\bf{answer} \div$

Length = 15m.

= 1500cm

Diameter = 20 cm

Radius = 10 cm.

Now,

Curved Surface Area of cylinder = 2πrh.

= 2 × 3.14 × 10 × 1500

= 2 × 314 × 150

= 94200 cm^2.

$\boxed{area \: painted = {94200cm}^{2} }$

Answer 2

Answer:

The pipe is 15 m long and 20 cm is the diameter .

The outer side walls of the pipe is painted .

This means that the area of painting is equal to the curved surface area of the pipe .

Area = 2 π r h

r = diameter/2

⇒ r = 20 cm / 2

⇒ r = 10 cm

h = 1500 cm

Area = 2 × 3.14 × 10 cm × 1500 cm

⇒ 20 cm × 15 × π cm

⇒ 30000 × 3.14 cm²

Area is 94200 cm² .

Step-by-step explanation:

A pipe is a cylinder . Curved surface area is defined as the area of the curvature of the pipe .

Area of cross section of a pipe is circular and the volume of a pipe is the area of cross section multiplied with the height .