Problem Solving Using Proportions Chapter 8.3 Problem Solving Using Proportions

Objectives I will use proportions to solve real-life problems. I will use similar triangles to measure objects indirectly.

Solving real-life problems Proportions are used in architecture and manufacturing to construct scale models. You can also use proportions to find dimensions.

Finding Dimensions You have a scale model of a Boeing 767. The model was built using a 1 – to 250 scale. The wing span on the model is 7 ½ in. What is the wing span of an actual 767?

Finding Dimensions Continued Step 1: Set up a proportion Step 2: Use Cross Product Property Step 3: Solve Equation 1875 = x The wing span of a 767 is 1875 in. Convert this measurement back into feet by dividing by 12. 1875 ÷ 12 = 156 ft.

Give it a try!  The scale on a map reads 1 in = 5 mi. Find the actual length of a road that is 2.5 in. long on the map. Step 1: Set up a proportion Step 2: Cross Multiply 1x = 12.5 x = 12. 5 miles

Finding the height of a building To estimate the height of the Transco Tower in Huston, Texas, you measure its shadow to be about 55 m. The shadow of a 50 m flagpole is about 10 m. Estimate the height of the Transco Tower.

Height of a building Step 1: Set up a proportion: Transco Tower Height = H Flagpole Height = h = 50 Transco Tower Shadow = D = 55 Flagpole Shadow = d = 10 Step 2: Cross Multiply and write an equation H (10) = 50 (55) 10 H = 2750 Step 3: Solve the equation: H = 275 The Transco Tower is about 275 m high.

Give it a try!  A meteorologist reports that the ratio of snowfall in January to total snowfall during the average winter is 2 to 5. If 34 inches have fallen in January of the current year, find the predicted total snowfall for the entire winter. Proportion: