Thread: Rectangle problem

1. Rectangle problem

Hello it's Liz again. I have another problem but I half way know what do. Here is the problem: If the sides of a square are lengthened by 8cm, the area becomes 225 cm^2. Find the length of a side of the original square.

This is what I have so far: x+8cm

2. Originally Posted by lizann
Hello it's Liz again. I have another problem but I half way know what do. Here is the problem: If the sides of a square are lengthened by 8cm, the area becomes 225 cm^2. Find the length of a side of the original square.

This is what I have so far: x+8cm
Here is a diagram

so to find the area of the big square we multiply the base times the height, but we know the area is 225 square cm so

$(x+8)(x+8)=225$

$(x+8)^2=225 \iff \sqrt{(x+8^2)}=\sqrt{225}$

$x+8=\pm 15 \iff x=-8 \pm 15$

Since length can't be negative we will only use the postive root

$x=-8+15=7$

So the length of the orginal square is 7 cm.

Yeah!!!

3. Thanks very much

Thank you very much you are extremely smart and well in math. I could really use a lot of help if you are willing to help. I'm placed in a math class that I don't really understand at all. I have done majority of the question i just have about five left. Can you help me with the rest of the math problems? If not thanks anyway you were a huge help. Problem better than my instructor.