EXAMPLE:
Sarah has 80 pieces of picture cards of vertebrates. The pie chart shows the classification of vertebrates.

SOLUTION:

a) What is the percentage of amphibians?

Percentage of amphibians:

100% - (25% + 20% + 15% + 35%) 

= 100% - 95%

= 5%

b) Find the difference between the number of mammals and bird picture cards.

\(\text{ Mammals} = \dfrac{25}{100}\times 80\text{ pieces}\\ \quad\quad\quad\space\space\space\space\space\space\space=20\text{ pieces}\)

\(\text{ Bird}= \dfrac{35}{100} \times 80\text{ pieces}\\ \quad\space\space\space\space\space\space = 28\text{ pieces}\)

The difference between the number of the picture cards of mammals and birds:

Mammal picture cards - Birds picture cards
= 28 pieces - 20 pieces
= 8 pieces