Math Question?

Question

The owner of a house paints this attic wall. There is a small rectangular window in the wall. The triangle's base is 4.2 metres and the height of the triangle is 4.5 metres. The base of the small rectangle is 60cm and the height is 150 cm. a) What is the area to be painted? Do you first find the area of the triangle and then you find the area of the rectangle? I dont get it? And please note that the base and height of the triangle is different than the base and height of the rectangle. And please explain so I can understand.

One litre of paint covers 6.5 m2. The area that is to be painted is 8.55 m2. Is it 1L and 2.05 mL.

Answer 1

First - Find the area of the triangle
Then - Find the area of the rectangle

Subtract the area of the rectangle from the area of the triangle and the answer is the area to be painted.

Answer 2

First, to make the problem easier on yourself, make sure all units are the same; so convert your meters in centimeters or vice versa. So instead of the base being 4.2 meters, it would be 420 cms. (You would do the same with the height; giving you 450 cms). Next, find the area of the triangle, the formula being base X height divided by 1/2, or .5. So, multiply 450 by 420 and then by 1/2. Giving you: 94500 cms. Then you have to minus the area of the small rectangular window and subtract it from the area of the wall, (because you're not going to paint over the window). So, to find the area of a rectangle, you simply multiply its base by its height. So, 150 cms X 60 cms, giving you 9000 cms. So, 94500 cms minus 9000 cms gives you the area of what you are going to be painting: 85500 cms or (converted back to meters by dividing by 100) 855 meters.

Answer 3

find the area of the triangle and the area of the rectangle. It doesn't matter which you do first.

Then subtract the window from the wall. The base of the window is different because it isn't as big as the whole wall.

4.2 * 4.5 = 18.9 sq meters
Change cm into m before you do the window
.6 * 1.5 = .9 sq meters
18.9 - .9 = 18 sq meters to paint

Answer 4

ok... first you find the rectangle's area then the triange's which would be: 60*150=9000 (rectangle) then you would find the area of the triangle (forgot how to do it so you have to srry!) then subract the rectangle FROM the triangle. you subtract because you aren't going to paint the window so you don't have to waste paint on that ,but i find these questions weird because if you were a painter... wouldn't you just paint the dang thing without all the math!!!! haha!! hope i helped!!! :D