Question

a metal pipe is 77 cm long the inner diametre of a cross section is 4 cm , the outer diamtere being 4.4 cm find its .

(1) inner curved surface area
2) outer curved surface area
3) area of two circular rings
4 ) total surface area
5 ) cost of painting its total surface area @ rs. 2.00 per cm²​

Answer 1

Answer:

refer the attachment above

Answer 2

Answer:

Step-by-step explanation:

Given

the height of metal pipe (h) = 77 cm

The inner diameter (d) = 4 cm

The inner radius (r) = d/2 = 4/2 cm = 2 cm

» The inner curved surface area (A) = 2πrh = 2×3.14×2×77 = 967.12 cm² [value of π = 3.14 (approx)]

The outer diameter (D) = 4.4 cm

The outer radius (R) = 2.2 cm

» The outer curved surface area (B) = 2πRh = 2×3.14×2.2×77 = 1063.83 cm²

Area of two circular rings = π(R²-r²) = 3.14(2.2² - 2²) ≈ 2.64 cm²

Total Surface Area (A+B) = 967.12+1063.83+2.64+2.64 = 2036.23 cm²

Cost to paint total Surface area @2.00 Rs = 4072.46 Rs