Presentation on theme: "Rectangle The area of a rectangle is by multiplying length and height. The perimeter of a rectangle is the distance around the outside of the rectangle."— Presentation transcript:
Rectangle The area of a rectangle is by multiplying length and height. The perimeter of a rectangle is the distance around the outside of the rectangle. A rectangle has a length of 8 centimeters and a width of 3 centimeters. Find the perimeter. Solution 1 - P = 8 cm + 8cm + 3 cm + 3 cm = 22 cm Solution 2 - P = 2(8 cm) + 2(3 cm) = 16 cm + 6 cm = 22 cm Example
Triangle multiply the base by the height, and then divide by 2. Find perimeter add a+b+c Find the perimeter, P, of the triangle shown below. Solution: So, the perimeter is 28 cm.
Parallelogram Example 1: Find the area of a parallelogram with a base of 12 centimeters and a height of 5 centimeters. Solution: A= b*h = (12 cm) · (5 cm) = 60 cm 2 The total distance around the outside of a parallelogram is the perimeter The area of a triangle is A= b*h
Circle Example The radius of a circle is 3 inches. What is the area? Solution: Area is A= 3.14 * r* r Perimeter is 2*3.14* r
Irregular Shape To find the area and perimeter of irregular shapes, the first thing to do is to divide the irregular shape into regular shapes that you can recognize such as triangles, rectangles, circles, squares and so forth... 1. Break down the irregular shapes into smaller shapes. 2. Find the edges of the smaller shapes. 3. Calculate the area of each small shape. 4. Add all of the areas of the small shapes (the sum will be the area of the irregular shape). Example