Finding the Area of Rectangles and Parallelograms TeacherTwins©2015

Warm Up Find the perimeter of each polygon. 1. 2. 3. 4. 156m 104m 9m

Finding the Area of Rectangles and Parallelograms

Area of a Rectangle Formula

Area of a rectangle = length x width

Ex. 1: Find the area of the rectangle. A = l x w A = 19cm x 12cm 12cm A = 228cm2 19cm

Ex. 2: Find the area of the rectangle. A = l x w A = 8cm x 2cm 2cm 8cm A = 16cm2

Another way to write the formula is Area = side x side or A = s2 . A square is a rectangle so to the find the area of a square use the rectangle formula. Since all sides of a square are congruent the area is found by finding 4 x 4. 4cm Another way to write the formula is Area = side x side or A = s2 . A = 16cm2

Ex. 3: Find the area of the square. A = s2 A =142 14 cm A = 196cm2

Practice Find the area. 1. 2. 126in2 36m2 4. 3. 27cm 34cm 225m2 918cm2 1. 2. 126in2 6m 9in 36m2 14in 4. 3. 27cm 15m 34cm 918cm2 225m2

Area of a Parallelogram Formula

Area of a parallelogram Area = base x height The base and height of a parallelogram must be perpendicular.

A = base x height A = 13m x 8m A =104m2 Ex.4: Find the area of the parallelogram. 8m 13m A = base x height A = 13m x 8m A =104m2

Ex. 5: Find the area. 8 2x + 3 A = 8(2x + 3) = 16x + 24

Practice Find the area of the parallelograms. 1. 2. 7cm 3cm 14cm 6cm

Closure If the area of the parallelogram is 150ft2, what is the base?