can you please help me with my homework I dont understand how to do it

Question

Benjamin visited an art show and saw a painting he really wanted to purchase but it was very expensive! In the gift shop, he found that he could by post cards of the paintings at a much more affordable price. The post card was 4 inches by 6 inches and it said that it was 2/7 the size of the original. What are the dimensions of the original painting?

Answer 1

If the postcard is 2/7 of the original, 

the original is 7/2 of the postcard.

Multiply the postcard dimensions by 7/2.

Answer 2

The post card is 2/7 of the original size.  This means that the ratio of the side of the post card to the side of the painting is 2/7.

 

We can set up two proportions to convert the sides lengths 4 and 6 to the painting lengths, x and y.

 

4/x = 2/7

2x = 28

x = 14

 

6/y = 2/7

2y = 42

y = 21

 

The painting is 14 inches by 21 inches.