11.4 Right Circular Cones

Given $h = 10, r = 24$. We need slant height $l$.

$l = \sqrt{h^2 + r^2} = \sqrt{10^2 + 24^2} = \sqrt{100 + 576} = \sqrt{676}$.

$l = 26$ m.

Canvas area = CSA (base is open). $CSA = \pi rl = \frac{22}{7} \times 24 \times 26$.

$CSA \approx 1961.14 \text{ m}^2$.

Cost = $1961.14 \times 70 = 137280$ (approx).

Exact calculation: $\frac{22}{7} \times 24 \times 26 \times 70 = 22 \times 24 \times 26 \times 10 = 137280$.