Question

A metallic pipe is 0.7 cm thick. Inner radius of the pipe is 3.5 cm and length is
5 dm. Find its total surface area.
Hint: Total surface area = Inner surface area + Outer surface area + Area of two rims]
find​

Answer 1

Given:

Thickness of the pipe is 0.7 cm

Inner radius (r) is 3.5 cm

length (height) is 5dm = 50 cm

[ as 10 cm = 1 dm ]

Outer radius (R) = (3.5 + 0.7) = 4.2 cm

To find :

Its total surface area ?

By using formula :

[Total surface area = Inner surface area + Outer surface area + Area of two rims]

Total surface area = 2π(r + R) (h + R - r) unit square

Total surface area = 2 × 22/7(3.5+4.2) (50+4.2-3.5) cm²

Total surface area = 44/7 × 7.7 × 50.7 cm²

Total surface area = 2453.88 cm²

Hence, total surface area = 2453.88 cm²