COURSE 2 LESSON 5 3 Draw a Diagram

COURSE 2 LESSON 5 -3 Draw a Diagram and Solve a Simpler Problem A cake is shaped like a rectangle that is 13 in. long and 9 in. wide. There is one candle at each corner of the cake, and there are candles at one-inch intervals along the edges of the cake. How many candles are there in all? The length of the cake is 13 in. long, and it is 9 in. wide. There is a candle in each corner, and at one-inch intervals along the edges. The goal is to find out how many candles are on the cake. 5 -3

COURSE 2 LESSON 5 -3 Draw a Diagram and Solve a Simpler Problem (continued) Method 1 Draw a Diagram Draw a diagram, such as the one at the right, that allows you to see where the candles are placed. There are 44 candles along the edges of the cake. 5 -3

COURSE 2 LESSON 5 -3 Draw a Diagram and Solve a Simpler Problem (continued) Method 2 Solve a Simpler Problem Instead of solving the problem for a 9 -in. by 13 -in. cake, change the problem to a simpler one based on a 2 -in. by 6 -in. cake, and then on a 3 -in. by 7 -in. cake. 5 -3

COURSE 2 LESSON 5 -3 Draw a Diagram and Solve a Simpler Problem (continued) Part of Cake 2 in. 6 in. Number of Candles 3 in. 7 in. Number of Candles First Corner 1 1 Short Side 1 2 Second Corner 1 1 Long Side 5 6 Third Corner 1 1 Short Side 1 2 Fourth Corner 1 1 Long Side 5 6 Total 16 20 5 -3

COURSE 2 LESSON 5 -3 Draw a Diagram and Solve a Simpler Problem (continued) There are 16 candles on a 2 -in. 6 -in. cake and 20 candles on a 3 -in. 7 -in. cake. You add 4 candles for each inch added to the length and width of the cake. So there are 44 candles on a 9 -in. 13 -in. cake. Your first thought might have been that there are 10 candles on each short side of the cake and 14 candles on each long side, and therefore you need 10 + 14 = 48 candles. Each side, however, shares each corner with another side, so you need 9 + 13 = 44 candles. 5 -3

COURSE 2 LESSON 5 -3 Draw a Diagram and Solve a Simpler Problem 1. What is the sum of the first fifty odd numbers? 2, 500 2. Alan cut a log into 4 pieces in 12 minutes. How long would it take him to cut a log of the same size into 6 pieces? 20 min 5 -3