Question

Choose the correct proportions.

21, 5, 15, 7

a) 5:21 = 7:15
b) 5:7 = 15:21
c) 5:7 = 21:15
d) 21:5 = 15:7

Answer 1

b) 5:7 = 15:21

Explanation:

This questions tests our understanding of enlargement ratios.

#Determine the decimal equivalents or simplify to see which one is correct:

#a) 5:21 = 7:15

`(5)/(7)=0.7143\\\\(7)/(15)=0.4667\\\\5:7\\eq 7:15`

#b) 5:7 = 15:21

`=(5)/(7)\\\\=(15)/(21)=(5)/(7) \# dividing \ by \ 3\\\\`
`(5)/(7)=(15)/(21)`

#c) 5:7 = 21:15

`(5)/(7)=0.7143\\\\(21)/(15)=1.4\\\\(5)/(7)\\eq (21)/(15)`

#d) 21:5 = 15:7

`(21)/(15)=1.4\\\\(15)/(7)=2.1429\\\\(21)/(15)\\eq (15)/(7)`

Hence, option b is the correct one as 5:7 = 15:21