Question

open cones are made from nets cut from a large sheet of paper 1.2m X 1.0m. If a cone has a radius of 6cm and a slant height of 10cm, how many cones can be made from the sheet? (Assume there is 5% wastage of paper)

Answer 1

r = 6 cm, l = 10 cm
The lateral surface of cone:
LSA = r l π = 6 · 10 · 3.14 = 188.4 cm²
Area of a paper:
A = 120 cm · 100 cm = 12 000 cm²
( with 5 % waste) 12 000 · 0.95 = 11 400 cm²
11 400 : 188.4 = 60.5
Answer: 60 cones.