11-1 Areas of Rectangles and squares

Formulas 1) Area of rectangle = base x height or length X width 2) Area of square = (side) 2 or base X height 3) Congruent shapes have the same area 4) Area of irregular shapes is the sum of the areas of its non-overlapping parts 5) Perimeter is the sum of the sides of the shape.

Examples 1. Find the Area and Perimeter of a rectangle with b=18 and height=3. A=bh so A=18(3)= 54 P=2b + 2h so P=2(18) + 2(3)=42 2. Find the Area and perimeter of a square with s=5 A=s 2 so 5 2 =25 P=4(5)=20

Example: Find the Area = = = = 67

TOO: Find the area of the shaded region 4x 12x 9x 18x 102x 2

Example: work backwards If the area of a rectangle is 120 m 2 and the height is 8 m, find the base. A = bh 120 = b(8) b = 15 m

TOO 1) If the perimeter of a rectangle is 100 in and the base is 40 in, find the height and area. 2) If the area of a rectangle is (y 2 + 7y) and the height is y, find the base and perimeter. Answers: 1) h = 10 in, A = 400 in 2 2) b = y + 7, P = 4y + 14

Example Find the area 4√3 4 8

TOO: Find the area Hint: rules 30 10

Homework Page 426 – 1-15 odd – all skip 21