# By doubling each dimension, the area of a parallelogram increased from 36 square centimeters to 144 square centimeters. How do you find the percent increase in area?

##### 1 Answer

Once you start to recognise the connections between numbers you will be able to do these much quicker than I have shown.

#### Explanation:

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We are only interested in the change in area. As both these values are given then anything else is a 'red herring'.

Assuming the increase is to be measured against the original area

Notice that for 108 that

Notice that for 36 that

So to simplify we have:

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Let the unknown value be

Then we are looking to end up with

To change 1 into 100 multiply by 100. What you do to the top you do to the bottom.

So we have the percentage