If the sides of a square is increased by 3cm, the area becomes 64 cm^2. How do you find the length of a side of the original square?

1 Answer
Oct 6, 2015

Answer:

The original size was #5 cm#

Explanation:

Let #a# be the original side of the square.

We know that if the side is increased by #3# the area of the new square is #64 cm^2#. So we can write that:

  1. #a >=0# because #a# is a geometrical dimension and they are never negative.
  2. The area of square with 3 cm longer sides is #64 cm^2#, so we can write #(a+3)^2=64#

Since we are only looking for positive values of #a# (because of pt. 1) we can take a square root of both sides of the equation to get: #a+3=8#.
Now after substracting #3# from both sides we get the answer: #a=5#