Question

a metal pipe is 77 CM long , the inner diameter of the cross section is 4 CM and the outer diameter is 4.8 CM. (1) inner curved surface area (2) outer curved surface Area (3) total surface area ​

Answer 1

$\bf{\underline{Question:-}}$

a metal pipe is 77 CM long , the inner diameter of the cross section is 4 CM and the outer diameter is 4.8 CM.

• inner curved surface area
• outer curved surface Area
• total surface area

$\bf{\underline{Solution: -}}$

A pipe will have two layers there is a inner Cylinder and Outer Cylinder. Let inner radius be r and outer radius be R.

→ r = Inner Diameter/2

→ r = 2/2 = 1 cm

and

→ R = Outer diameter/2

→ R = 2.2/2 = 1.1 cm

As we know that

CSA of Cylinder = 2πrh

• Inner CSA = 2(22/7)(1)(77)

→ 44(11)

→ 484 cm²

So,

• inner CSA is 484 cm².

Now,

• outer CSA = 2πRh

• Outer CSA = 2(22/7)(1.1)(77)

→ 44(1.1)(11)

→ 532.4 cm²

• So outer CSA is 532.4 cm²

→ TSA = Inner csa + Outer csa + 2π(Cross section surface area)

→ TSA = 484 + 532.4 + 2(22/7)(R² – r²)

→ 1016.4 + 44/7(1.1² – 1²)

→ 1016.4 + 44/7(1.21 – 1)

→ 1016.4 + 44/7(0.21)

→ 1016.4 + 44(0.03)

→ 1016.4 + 1.32

→ 1017.72

$\bf{\underline{Hence:-}}$

• inner CSA is 484 cm².
• outer CSA is 532.4 cm²
• TSA will be 1017.72 cm²