Quick Notes

EXAMPLE 1

There is a cube and one surface of the cube has a perimeter of 16 cm. Calculate the volume of the cube.

SOLUTION:
The perimeter of a cube's surface is the perimeter of a square.
A square has 4 sides with equal length.

Length of a side:
\(\text{Perimeter}\div4= 16\div 4 = 4\text{ cm}\)

A cube has the same length, width and height.

Volume of the cube: 
\(\text{Length}\times\text{Width}\times\text{Height}=4\times 4\times 4 = 64\text{ cm}^3\)

EXAMPLE 2

Find the area of a triangle with height of 8 cm and base of 4 cm.

SOLUTION:
Area of a triangle:
\(\frac{1}{2}\times \text{Height}\times \text{Base}=\frac{1}{2}\times 8\times4= 16\text{ cm}^2\)