Page 1 of 4 Perimeter and Area BEFORE Now WHY? You used properties of rectangles and squares. You’ll use formulas to find perimeter and area. So you can find the area of a theater’s stage, as in Ex. 22. 3 units The perimeter of a rectangle is the sum of the lengths of the sides. Perimeter is measured in linear units such as inches (in.), feet (ft), centimeters (cm), and meters (m). Word Watch perimeter, p. 32 area, p. 32 2 units 2 units 3 units The area of a rectangle is the number of square units needed to cover the rectangle. Area is measured in units such as square inches (in.2), square feet (ft2), square centimeters (cm2), and square meters (m2). Perimeter 3 3 2 2 10 units Area 6 square units You can use formulas to find perimeter and area. Perimeter and Area Rectangle Square width w side length s length l Perimeter P P 2l 2w P 4s Area A A lw A s2 EXAMPLE with Notetaking If you forget the formula for the perimeter of a rectangle, you could draw and label a diagram like the one shown at the top of this page. Then just add the lengths of the sides. 1 Finding Perimeter Find the perimeter of the rectangle or square with the given dimensions. a. l 5 feet, w 2 feet Solution a. P 2l 2w Chapter 1 b. P 4s 2(5) 2(2) 4(3) 10 4 14 12 ANSWER The perimeter is 14 ft. 32 b. s 3 centimeters Number Sense, Patterns, and Algebraic Thinking ANSWER The perimeter is 12 cm. Page 2 of 4 Your turn now Find the perimeter of the rectangle or square. 1. 2. 1 in. 8 cm 7 in. EXAMPLE with Review Need help with rectangles and squares? See p. 701. 2 Finding Area Find the area of the rectangle or square with the given dimensions. a. l 5 inches, w 3 inches b. s 10 feet Solution b. A s 2 a. A lw 5(3) 102 15 100 ANSWER The area is 15 in.2. Your turn now ANSWER The area is 100 ft 2. Find the area of the rectangle or square. 3. 4. 2m 11 ft 6m 5. Find the perimeter and the area of a rectangle that has a length of 6 inches and a width of 4 inches. EXAMPLE 3 Using Perimeter and Area Wheelchair Slalom In a wheelchair slalom event, athletes weave around cones and race to the finish line. A diagram of the rectangular course is shown. Find the perimeter and the area of the course. Start 16 m 30 m Solution P 2l 2w A lw 2(30) 2(16) 30(16) 60 32 92 480 Finish ANSWER The perimeter of the course is 92 m, and the area is 480 m2. Lesson 1.6 Perimeter and Area 33 Page 3 of 4 INTERNET Exercises eWorkbook Plus CLASSZONE.COM More Practice, p. 705 Getting Ready to Practice Vocabulary Copy and complete the statement. 1. The sum of the lengths of the sides of a rectangle is the _?_ of the rectangle. 2. The number of square units needed to cover a rectangle is the _?_ of the rectangle. Find the perimeter and the area of the rectangle or square with the given dimensions. 3. l 12 inches, w 4 inches 4. l 9 meters, w 7 meters 5. s 7 centimeters 6. s 2 centimeters 7. Art A rectangular painting has a width of 4 feet and a length of 7 feet. Find the perimeter and the area of the painting. with Example 1 2 3 Homework Exercises 8–17 8–17 18, 20, 22 Online Resources Practice and Problem Solving Find the perimeter and the area of the rectangle or square. 8. 3m 15 m 9. 20 in. CLASSZONE.COM • More Examples • eTutorial Plus Find the perimeter and the area of the rectangle or square with the given dimensions. 10. l 20 feet, w 2 feet 11. s 4 centimeters 12. s 9 meters 13. l 11 inches, w 6 inches 14. l 15 feet, w 4 feet 15. s 12 centimeters 16. s 13 inches 17. l 8 meters, w 5 meters 18. Gardening You plant a rectangular garden that has a length of 20 feet and a width of 8 feet. Find the perimeter and the area of the garden. 19. Compare Which has the greater area: a rectangle with a length of 7 feet j7pe-0106-004-h and a width of 5 feet, or a square with a side length of 6 feet? Explain how you know. 20. Basketball A high school basketball court is a rectangle with a length of 84 feet and a width of 50 feet. What is the perimeter of the court? 34 Chapter 1 Number Sense, Patterns, and Algebraic Thinking Page 4 of 4 21. Measurement Measure the sides of the rectangle to the nearest inch. Use your measurements to find the perimeter and the area. History 22. Globe Theatre William Shakespeare’s plays were performed on the stage of the old Globe Theatre in London. The rectangular stage had a length of 43 feet and a width of 28 feet. Find the area. Critical Thinking Find the unknown dimension of the rectangle or square. 24. A 8 ft2, l 4 ft, w _?_ 23. P 24 in., s _?_ Challenge The figures below can be broken into rectangles and squares. Find the perimeter and the area of each figure. Explain your method. 25. 26. 5 ft 7m 1 ft ■ Globe Theatre The old Globe Theatre was built in 1598, but it no longer exists. A new Globe Theatre was opened in 1997. It has a rectangular stage with a length of 44 feet and a width of 25 feet. What is the area of the new Globe’s stage? 6m 3 ft 3m 3m 2m 2 ft Mixed Review 27. You save $3 in September. The next three months you save $6, $12, and then $24. If this savings pattern continues, how much will you save in January? (Lesson 1.1) Solve the equation using mental math. (Lesson 1.5) 28. 4c 32 29. 16 a 11 30. x 18 25 Basic Skills Copy and complete the equation. 31. 6 _?_ 13 32. _?_ 8 19 33. 14 _?_ 2 Test-Taking Practice INTERNET State Test Practice CLASSZONE.COM 34. Multiple Choice What is the area of a rectangular desktop that has a length of 5 feet and a width of 2 feet? A. 10 in.2 B. 14 ft C. 10 ft2 D. 14 ft2 35. Short Response Does a rectangular garden with a length of 6 feet and a width of 4 feet, or a square garden with side length 5 feet, have the greater area? Which requires more fencing? Explain. Lesson 1.6 Perimeter and Area 35