There are 3 feet in 1 yard. this is equivalent to 12 feet in 4 yards. which proportion can be used to represent this?

Proportion which can be used to represent equivalency of 3 feet in 1 yard and 12 feet in 4 yard is 3 : 1 : : 12 : 4

Given that

There are 3 feet in one yard  

And there are 12 feet in 4 yard  

Number of feet in one yard = 3 that is feet  : yard = 3 : 1  

Number of feet in 4 yards = 12 that is feet : yard = 12 : 4  

And 3 feet in 1 yard is equivalent to 12 feet in 4 yards means

That is 3 : 1 : : 12 : 4

A proportion is statement that two ratios are equal. It can be written in two ways: as two equal fractions a/b = c/d; or using a colon, a : b = c : d

Hence proportion which can be used to represent equivalency of 3 feet in 1 yard and 12 feet in 4 yard is 3 : 1 :: 12 : 4