How do u find if the following numbers are in proportion= (a) 15,20,30,40, (b) 1,2,2,4, (c) 18,36,144,288 [Please I - Maths - Ratio and Proportion

Question

How do u find if the following numbers are
in proportion= (a) 15,20,30,40, (b) 1,2,2,4, (c) 18,36,144,288
[Please I need to know the method even]

Manmeet Singh · Accepted Answer

Suppose we have four numbers, a, b, c, d

They are said to be in proportion if $\frac{a}{b} = \frac{c}{d}$

consider the numbers, 15, 20, 30, 40

$\frac{15}{20} = \frac{3}{4} a n d \frac{30}{40} = \frac{3}{4} ∴ \frac{15}{20} = \frac{30}{40}$

Hence the numbers, 15, 20, 30, 40 are in proportion.

This can verified in the other two parts.

How do u find if the following numbers are in proportion= (a) 15,20,30,40, (b) 1,2,2,4, (c) 18,36,144,288. [Please I need to know the method even].