260/500 = 13x20/25x20 = 13/25
13 x 20 = 260 The area of the floor is 260 square feet. The area of the ceiling is also 260 square feet. The area of the walls can't be calculated without also knowing the height of the room.
The formula for area of a triangle is base times height divided by 2, A=BxH/2 So if you're referring to "20 cm and 13 cm" as the base and height, 13x20=260, 260/2=130, so the answer is 130 square cm. :D
Perimeter is used in several real world situations.For example, if your living room is thirteen feet long and twenty feet wide, you know you can't get a rug whose sides are bigger than 13x20.Another common example is fencing. When you are putting up a fence you don't really care about the area. You are looking for how much fencing you will need, which means you need to know how big the perimeter of the land is.In math, perimeter is used in geometry and trigonometry (among other places), and is sometimes used to help student's practice their algebra skills is middle schools.