## Tuesday, November 9, 2010

### Alvin's Blog Post Novemeber 9, 2010

Hello Fellow Classmates,

Today in class we were all assigned questions from the textbook. I was assigned question 19 on pg 79.

19. A square picture with an area of 100cm is mounted on a square piece of matting. The matting has 2.5 times the area of the picture. If the picture is centered on the matting what width of the matting is visible around the outside of the picture ? Give your answer to the nearest tenth of a centimeter.

First of all if the matting is 2.5 times the size of the picture, then the picture would be 250 cm ( 2.5 x 100 ). Then the picture is placed in the center of the matting so then we take away the area of the picture from the matting, so its ( 250 - 100 = 150). So now the area of the matting is 150cm, so now we have to find the width of the matting. First the sides of the pictures are 10cm because the area of the picture is 100 ( 10x10 = 100). The lengths of the sides of the matting is 12.2 since 150 squared is 12.24744871 ( I just rounded it ). So now since there is 2 sides on the picture since its placed in the middle the width of one side would be 1.1cm because (12.2 - 10 divided by 2) since there is two widths.

I tried my best to explain this and I'm sorry if you don't understand ):
(it's plain since my colour wont work