Question
Mathematics Question on Surface Area of a Right Circular Cone
A conical tent is 10 m high, and the radius of its base is 24 m. Find.
(i) slant height of the tent.
(ii) cost of the canvas required to make the tent, if the cost of 1 m2 canvas is 70.
Answer
(i) Let ABC be a conical tent.
Height (h) of conical tent = 10 m
Radius (r) of conical tent = 24 m
Let the slant height of the tent be l.
In ∆ABO, AB2 = AO2 + BO2
l2 = h2 + r2
= (10 m)2 + (24 m)2
I= 676
= 26 m
Therefore, the slant height of the tent is 26 m.
(ii) curved surface area of the cone = πrl
= 722 × 24 m × 26 m
= 713728m²
The cost of the canvas required to make the tent, at ₹ 70 per m² = 70 × Curved surface area of the cone
= 713728 × 70
= ₹137280
Thus, slant height of the tent is 26 m and the cost of the canvas is ₹ 137280.