Question

Determine if the following are in proportion 

(i) 3 : 5 and 1 : 15 

(ii) 4 : 12 and 9 : 27 

(iii) Rs. 10, is to Rs. 15 and 4 is to 6

Answer 1

(i) 3 : 5 = 1 : 15 = 3 × 15 = 5 × 1 

45 ≠ 5 

∴ 3 : 5 and 1 : 15 are not in proportion 

(ii) 4 : 12 and 9 : 27 

⇒ 4 : 12 = 9 : 27 

⇒ 4 × 27 = 12 × 9 

⇒ 108 = 108 

∴ 4 : 12 and 9 : 27 are in proportion 

(iii) 10 : 15 = 4 : 6 

⇒ 10 × 6 = 15 × 4

 ⇒ 60 = 60 

∴ Given numbers are in proportion.