Question 67

The radius of the base of a conical tent is 5 m and its height is 12 m. how many metres of canvas of width 5 metres will be required to make it?(use $$\pi = \frac{22}{7}$$ )

Solution

Slant height of cone = $$l=\sqrt{(12)^2+(5)^2}=\sqrt{144+25}$$

=> $$l=\sqrt{169}=13$$ m

Let canvas required be $$x$$ m

Curved surface area of cone = $$\pi rl=5\times x$$

=> $$\frac{22}{7}\times5\times13=5x$$

=> $$x=\frac{286}{7}=40\frac{6}{7}$$ m

=> Ans - (B)

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