How do you solve #\frac { a } { 7} = \frac { 12} { 21}#?

2 Answers
Apr 28, 2017

a = 4

Explanation:

In order to find the value of the pro-numeral - a, we will use two simple steps:

  1. Find if the denominator of the left side of the fractions equation is divisible by the other side (in this case it is)

  2. Complete the same operation on the numerator as the denominator.

Apr 28, 2017

#a=4#

Explanation:

Solve:

#a/7=12/21#

Simplify #12/21#.

#a/7=(12-:3)/(21-:3)#

#a/7=4/7#

Multiply both sides by #7#.

#7xxa/7=4/7xx7#

Simplify.

#color(red)cancel(color(black)(7))xxa/color(red)cancel(color(black)(7))=4/color(red)cancel(color(black)(7))xxcolor(red)cancel(color(black)(7))#

Simplify.

#a=4#