# How do you find the ratio of a to b in lowest terms if a= 12 cm and b= 84 cm?

Apr 3, 2015

The ratio of $a : b$ is $1$ cm $: 7$cm.

Given $a = 12$ cm and $b = 84$ , the ratio $a : b$ would be
$12$cm : $84$cm

Dividing both sides by $12$ gives us:
$1$cm $: 7$cm

Apr 3, 2015

Try to divide both by the same number

$\frac{a}{b} = \frac{12}{84} =$ (divide both by 12 and you get) $= \frac{1}{7}$

You can do this step by step if you're not good at your multiplication tables (we'll do 2-2-3):

$\frac{a}{b} = \frac{12}{84} = \frac{6}{42} = \frac{3}{21} = \frac{1}{7}$