## 16 Surface area and volume of sphere circumscribing a regular tetrahedron

Example 016
Find the area of the surface and the volume of the sphere circumscribed about a regular tetrahedron of edge 25 cm. See Figure 015. ## 15 Volume of water necessary to cover two unequal spheres inside a cylindrical jar

Example 015
Two balls, one 15 cm in diameter and the other 10 cm in diameter, are placed in a cylindrical jar 20 cm in diameter, as shown in Figure 014. Find the volume of water necessary to cover them. ## 13 Compare the volume of a sphere inscribed in a cube with volume of the sphere that circumscribes the cube.

Example 13
Compare the volume of a sphere inscribed in a cube with volume of the sphere that circumscribes the cube.

## 12 Volume and total area of sphere circumscribing a cylinder of altitude and diameter each equal to 6 inches

Example 12
Find the volume and total area of the sphere which circumscribes a cylinder of revolution whose altitude and diameter are each 6 inches.

## 07 - 08 Volume and surface area of earth and balloon

Example 07
A spherical balloon is inflated so that so that its diameter is 12 m. Find the surface area of the balloon’s covering and the volume of the gas.

Example 08
Find the volume and total surface area of the earth. (Consider the earth a perfect sphere of diameter 7960 miles.)

05 Weight of 1000 pcs ivory billiard balls Jhun Vert Sun, 05/03/2020 - 11:06 am

Example 05
A cubic foot of ivory weighs 114 lb. Find the weight of 1000 ivory billiard balls 2½ inch in diameter.

03 Weight of an 5-cm thick iron shell with 50-cm external diameter Jhun Vert Sun, 05/03/2020 - 10:50 am

Example 03
An iron ball 10 cm in diameter weighs 4 kg. Find the weight of an iron shell 5 cm thick whose external diameter is 50 cm.

02 Weight of snow ball 1.2 m in diameter Jhun Vert Sun, 05/03/2020 - 10:47 am

Problem 02
Find the weight of the snowball 1.2 m in diameter if the wet compact snow of which this ball is made weighs 480 kg/m3

## 01 Solid steel ball remolded into hollow steel ball

Problem 01
A 523.6 cm3 solid spherical steel ball was melted and remolded into a hollow steel ball so that the hollow diameter is equal to the diameter of the original steel ball. Find the thickness of the hollow steel ball.