Warm Up Problem of the Day Lesson Presentation Lesson Quizzes

Warm Up 1. What is the perimeter of a square with side lengths of 15 in.? 2. What is the perimeter of a rectangle with length 16 cm and width 11 cm? 60 in. 54 cm

Problem of the Day Two wibbles equal four wabbles, and eight wabbles equal two bibbles. If a square has a perimeter of 16 wibbles, what is its area in square bibbles? 4 square bibbles

Sunshine State Standards MA.6.A.3.4 Solve problems given a formula. Also MA.6.A.4.2

Vocabulary area

The area of a figure is the amount of surface it covers The area of a figure is the amount of surface it covers. We measure area in square units.

Additional Example 1: Estimating the Area of an Irregular Figure Estimate the area of the figure. Count full squares: 19 red squares. Count almost-full squares: 9 blue squares. Count squares that are about half- full: 4 green squares = 2 full squares. Do not count almost empty yellow squares. Add. 19 + 9 + 2 = 30 The area of the figure is about 30 mi . 2

Estimate the area of the figure. Check It Out: Example 1 Estimate the area of the figure. = 1mi2 about 18 mi2.

Additional Example 2: Finding the Area of a Rectangle Find the area of the figure. A = lw 15 in. Write the formula. A = 15 • 9 9 in. Substitute 15 for l and 9 for w. A = 135 Multiply. The area is about 135 in2.

Find the area of each rectangle.. Check It Out: Example 2A Find the area of each rectangle.. 70 ft. 11 ft. A = lw = 70 × 11 = 770 The area is 770 ft . 2

Find the area of each rectangle.. Check It Out: Example 2B Find the area of each rectangle.. 12 mi. 9 mi. A = lw = 12 × 9 = 108 The area is 108 mi. 2

You can use the formula for the area of a rectangle to write a formula for the area of a parallelogram. Imagine cutting off the triangle drawn in the parallelogram and sliding it to the right to form a rectangle. The area of a parallelogram = bh. The area of a rectangle = lw. The base of the parallelogram is the length of the rectangle. The height of the parallelogram is the width of the rectangle.

Additional Example 3: Finding the Area of a Parallelogram Find the area of the parallelogram. A = bh Write the formula. Substitute 2 for b and 1 for h. 1 2 __ 4 1 A = 2 • 1 1 2 __ 4 1 ft 4 1 2 ft A = • 5 2 __ 4 2 Multiply. A = or 3 25 8 ___ 1 __ The area is 3 ft2. 1 8 __

Find the area of each parallelogram. Check It Out: Example 3A Find the area of each parallelogram. 8 ft 7 ft A = bh = 8 × 7 = 56 The area is 56 ft . 2

Find the area of each parallelogram. Check It Out: Example 3B Find the area of each parallelogram. 5.6 m 12 m A = bh = 5.6 × 12 = 67.2 The area is 67.2 m . 2

Additional Example 4: Recreation Application Jessika is going to tile a kitchen that measures 13 ft by 17 ft. Some floor space is taken up by an island that measures 3 ft by 6 ft. How much area remains to be tiled in the kitchen? To find the area to be tiled, subtract the area of the island from the area of the floor. floor area – island = kitchen area to be tiled Substitute for l and w in A = lw. (13 • 17)‏ – (3 • 6)‏ = n 221 – 18 = 203 Use the order of operations. The area of the kitchen to be tiled is 203 ft2.

What is the area that will be painted? Check It Out: 4 What is the area that will be painted? The figure shows a wall of an office with three identical windows. An employee is going to paint this wall of the office 18 × 8 = 144; 3 × 2.5 = 7.5; 144 - (3 × 7.5) = 144 - 22.5 The area that will be painted is 121.5 ft . 3 ft 8 ft 2.5 ft = 121.5 18 ft 2