Similar Figures We are learning to…use proportional reasoning to solve for missing side lengths of polygons. Tuesday, October 27, 2015

Similar Figures What does it mean for figures to be congruent? What does it mean when figures are similar? Similar Figures – Figures that are the same shape but different sizes. What makes polygons the same shape? They have the same angle measurements

Similar Figures Create Ratios to compare CORRESPONDING sides of the two similar figures below. Remember to write the ratios in simplest form. Sides that “match up.” A B C J K L First set of corresponding sides Second set of corresponding sides Third set of corresponding sides 4 cm 6 cm 8 cm 12 cm 10 cm 15 cm What do you notice about the ratios of corresponding sides?

Similar Figures If similar figures create equal ratios then we can create proportions. This will help us when if we did not know one of the side lengths of similar figures.

Similar Figures Solve for the missing side GH. T U V F G H 10 ft 15 ft 20 ft 8 ft 6 ft Create a table to organize your thinking: Triangle TVU Triangle FGH UV = 10 ft GH = x TV = 15 ft FH = 6 ft Write a sentence to explain your solution: (10) Create a Proportion and show your solution process: “Side GH is 4 feet long.”

Similar Figures Solve for the missing side KD. K D U B J 16 m 8 m 12 m 28 m 14 m Create a table to organize your thinking: Quadrilateral KDSR Quadrilateral ZJUB KD = x JZ = 35 m SD = 16 m UJ = 28m Write a sentence to explain your solution: (35) Create a Proportion and show your solution process: “Side KD is 20 meters long.” S 35 m Z 21 m R

Group Practice Work with your group to find the following missing side lengths of similar polygons. Create a table to organize your thinking. Set up a proportion and show every step of your solution process. Write your solution in the sentence form to explain your solution. Pick one leader per group. The group leader is in charge of: Reading the question to the group. Keeping the entire group on the same question at the same time. Checking to make sure that everyone in the group understand how the group found their solution. Raising their hand and asking the teacher a question if the whole group cannot agree on a solution process.