12.3. Model Perimeter Formulas. Unlock the Problem. Essential Question. Name

Transcription

1 ? Name 12.3 Essential Question Model Perimeter Formulas How can you use a formula to find the perimeter of a rectangle? lgebraic Reasoning 4.5., 4.5. MTHEMTIL PROESSES 4.1., 4.1.F Unlock the Problem Julio is putting a stone border around his rectangular garden. The length of the garden is 7 feet. The width of the garden is 5 feet. How many feet of stone border does Julio need? ircle the numbers you will use. What are you asked to find? Perimeter is the distance around a figure. To find how many feet of stone border Julio needs, find the perimeter of the garden. Use addition. Perimeter of a Rectangle = length + width + length + width 7ft The perimeter is _ feet. So, Julio needs _ feet of stone border. Use multiplication. Find Perimeter of a Rectangle Perimeter = (2 length) + (2 width), or 2l + 2w 8 cm 5ft Find Perimeter of a Square Perimeter = 4 one side, or 4 s 12 cm 12 cm Houghton Mifflin Harcourt Publishing ompany Image redits: 8 cm Perimeter = (2 12) + (2 8) = So, the perimeter is _ centimeters. Perimeter = 4 16 So, the perimeter is _ inches. Module

2 Use a Formula formula is a mathematical rule. You can use a formula to find perimeter. P = ( 2 l ) + ( 2 w ) perimeter length width length width Example Find the perimeter of the rectangle. P = (2 l ) + (2 w ) = (2 _ ) + (2 _) +_ Think: Write the measures you know. Think: o what is in parentheses first. 18 m 14 m The perimeter of the rectangle is. Share and Show 1. Find the perimeter of the rectangle. P = ( _ _ ) + ( _ _ ) = ( _ _ ) + ( _ _ ) + _ 8 ft 4 ft Formulas for Perimeter Rectangle: P = (2 l ) + (2 w) or P = 2l + 2w Square: P = 4 s, or P = 4s The perimeter is _ feet. Find the perimeter of the rectangle or square yd m 4 m 16 yd 110 m 4 m 422 _ yards _ meters _ meters Math Talk Mathematical Processes an you use the formula P = (2 l ) + (2 w) to find the perimeter of a square? Explain. Houghton Mifflin Harcourt Publishing ompany

3 Name Unlock the Problem 5. Multi-Step lejandra plans to sew fringe on a scarf. The scarf is shaped like a rectangle. The length of the scarf is 48 inches. The width is one half the length. How much fringe does lejandra need? 72 inches 120 inches 96 inches 144 inches a. raw a picture of the scarf, and label the given measurements on your drawing. b. What do you need to find? c. What formula will you use? d. Show the steps you use to solve the problem. e. omplete. The length of the scarf is _ inches. The width is one half the length or _ 2. The width is _ inches. So, the perimeter is (_ _) + (_ _) inches. Fill in the bubble for the correct answer choice above. Houghton Mifflin Harcourt Publishing ompany 6. Reasoning What is the side length of a square with a perimeter of 44 centimeters? 4 centimeters 11 centimeters 22 centimeters 176 centimeters 7. pply Mr. Wong is putting a brick edge around his rectangular patio. What is the perimeter of the patio? 18 ft 10 ft 28 ft 38 ft 56 ft 66 ft Module 12 Lesson 3 423

4 aily ssessment Task Mathematical Processes Fill in the bubble completely to show your answer. 8. rectangular swimming pool is 24 feet long and 12 feet wide. What is the perimeter of the swimming pool? 288 ft 60 ft 36 ft 72 ft 9. Todd is putting a fence around a square shaped section of his backyard. The square section is 102 m on each side. How many meters of fence does Todd need in all? 102 m 102 m 408 m 800 m 104 m 204 m 10. Multi-Step Joe is putting pavers around his rectangular patio. The width of the patio is 14 feet. The length is three times the width. How many feet of pavers does he need? 34 ft 112 ft 588 ft 168 ft TEXS Test Prep 11. Lola is putting a border on the quilt she is making. The quilt is shaped like a rectangle. The width of the quilt is 48 inches and its length is twice its width. How much border does Lola need? inches 288 inches 144 inches 192 inches Houghton Mifflin Harcourt Publishing ompany

5 Homework and Practice Name lgebraic Reasoning 4.5., 4.5. MTHEMTIL PROESSES 4.1., 4.1.F 12.3 Model Perimeter Formulas Find the perimeter of the rectangle or square ft 6 yd 8 ft 6 yd feet yards 3. 5 m 4. 9 in. 3 in. 4 m meters inches yd 48 m 80 yd yards 32 m meters Houghton Mifflin Harcourt Publishing ompany Problem Solving 7. Mrs. Sanders will put a border around a bulletin board that is 52 inches long and 30 inches wide. How many inches of border will she need? 8. rectangular room is 10 meters wide and 14 meters long. What is its perimeter? Module 12 Lesson 3 425

6 Lesson heck TEXS Test Prep Fill in the bubble completely to show your answer. 9. What is the side length of a square with a perimeter of 60 meters? 240 meters 30 meters 4 meters 15 meters 10. Robert wants to put lights around the edge of his yard. The yard is 40 feet long and 25 feet wide. How many feet of lights does he need? 1000 feet 130 feet 100 feet 160 feet 11. Each side of a table is 3 meters long. What is the perimeter of the table? 30 meters 9 meters 6 meters 12 meters 12. The movie screen at the cinema is 70 feet long and 30 feet wide. What is the perimeter of the screen? 200 feet 140 feet 60 feet 2100 feet 13. Multi-Step Marcia will make a frame for her picture. The length of the picture is 15 inches. The width is one third of the length. How much wood does Marcia need for the frame? inches 40 inches 30 inches 45 inches 14. Multi-Step Greg will build a fence for his yard. The width of the yard is 12 feet. The length of the yard is twice its width. How much fencing will Greg need for his yard? 60 feet 48 feet 24 feet 72 feet Houghton Mifflin Harcourt Publishing ompany