The radius

A right circular cone's radius and slant heights are 9 cm and 15 cm, respectively. Find, correct to one decimal place, the
(i) Height
(ii) Volume of the cone

Correct answer:

h =  12 cm
V =  1017.9 cm³

Step-by-step explanation:

$$\begin{gathered} r=9\text{cm} \\ s=15\text{cm} \\ {s}^2=h^2+r^2 \\ h=\sqrt{s^2-r^2}=\sqrt{15^2-9^2}=12\text{cm} \end{gathered}$$

$V=\frac{1}{3}\cdot \pi \cdot r^2\cdot h=\frac{1}{3}\cdot 3.1416\cdot 9^2\cdot 12=1017.9{\text{cm}}^3$

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