8.2 RATIQ, PROPORTION & RATE We can use a ratio to find a missing component when we compare two similar objects or things
as shown in the example below.
EXAMPLE: A tree 30 metres high casts a shadow 40 metres long. What is the height of a tree
whose shadow is 100 metres long?
30 m tree 40 m shadow
(We place the trees over the trees
100 m shadow on the left and the shadows over the
40x 3000
shadows on the right and solve the
40
equation by cross-multiplying.)
X = 75
40
:: the tree is 75 metres high.
A. Solve the following problems involving rate, ratio and proportion.