The area of a rectangle is 20 cm² after its dimensions were doubled. What is the area of the original parallelogram?

Question

Hi, I'm Benzie and I need help with my homework. May someone please take the time out and help me I would truly appreciated it. :)

 

Benzie

Answer 1

There are actually three possible answers here.  A = L x W.  So there's a multiplication problem used to find area. Your job is to find out, what two numbers were multiplied to find the area of the new rectangle and ask yourself "can I cut those in half and have them still be whole numbers?"

 

The trick is knowing the factors of 20 which are 1 & 20, 2 & 10 and 5 & 4.  If we're going on whole numbers only, which I'm assuming we are, which of those factors, well any of those factors can be cut in half or reverse doubled.  Try 1 & 20, well that would be .5 and 10.  At any rate, which of those factors can be cut in half (reverse doubled or divided by two in better math language) and remain whole numbers?

 

We already tested 1 & 20, we only had one whole number.  Try the other factors.  When you find the factors that divide evenly and stay whole numbers, you have found your original dimensions.  

 

Let me know what you come up with.