Question

State which of the following are proportions. 

(i) 2 : 3 :: 6 : 9 

(ii) 1 : 3 :: 4 : 15 

(iii) 3 : 5 :: 6 : 15 

(iv) 7 : 9 :: 14 : 18

Answer 1

(i) 2 × 9 = 3 × 6 

18 = 18 

It is a proportion 

(ii) 1 × 15 ≠ 3 × 4 

It is not a proportion 

(iii) 3 × 15 ≠ 5 × 6 

∴not a proportion 

(iv) 7 × 18 = 9 × 14

126 = 126 

It is a proportion