Question

Check whether the following are in proportion? or not?

(a) 8, 13, 17, 19 

(b) 30, 24, 20, 16

Answer 1

a) 8, 13, 17, 19 

Given numbers are 8, 13, 17,19. 

If a, b, c, d are in proportion i.e., a : b :: c : d, 

then the product of extremes = product of means (a.d = b.c)

8 × 19 = 13 × 17 

152 ≠ 221 

Here the product of extremes is not equal to the product of means, then the given numbers are not in proportion.

So, 8,13, 17 and 19 are not in proportion. 

b) 30, 24, 20, 16 

Given numbers are 30, 24, 20, 16. 

If a, b, c, d are in proportion i.e., a : b :: c : d, 

then the product of extremes = product of means (a.d = b.c) 

30 : 24 :: 20 : 16 

480 = 480 

Here the product of extremes is equal to the product of means, then the given numbers are in proportion. 

So, 30, 24, 20 and 16 are in proportion.