Ten solid spheres of radius 3 cm are melted into a pentagonal pyramid of height 18 cm. Using \(\pi=3

Question

Ten solid spheres of radius 3 cm are melted into a pentagonal pyramid of height 18 cm. Using $\pi=3.142$, find $h=18\text{ cm}$ Pentagonal base Central section

Accepted Answer

(i) Melting preserves volume: $V=10\left(\dfrac43\pi3^3\right)=360\pi=1131.12\text{ cm}^3$. (ii) $\dfrac13 A(18)=360\pi$, so $A=60\pi=188.52\text{ cm}^2$.

Recasting spheres as a pyramid

Recasting spheres as a pyramid

Solution:

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