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Indirect Measurement. Warm-Up Solve each proportion. 3 X 2. 6 2.4 5 75 X 8 3. 9 X 4. X 8 27 6 3.5 7. =. =. X = 20. X = 45. =. =. X = 2. X = 4. What we are doing….
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Warm-UpSolve each proportion. • 3 X 2. 6 2.4 5 75 X 8 3. 9 X 4. X 8 27 6 3.5 7 = = X = 20 X = 45 = = X = 2 X = 4
What we are doing… Learn to find measures indirectly by applying the properties of similar figures.
A F B C A A A A E G B B B B C C C C Indirect Measurement…. Notice how all angles are congruent. Which angle corresponds with angle F? Which angle corresponds with angle E? B A B Notice what happens as we turn the triangle. A
F B 3 ft 9 ft A C 4 ft E G X Example 1; Triangles ABC and EFG are similar. Find the length of side EG. Triangles ABC and EFG are similar.
Question 1: 1. Vilma wants to know how wide the river near her house is. She drew a diagram and labeled it with her measurements. How wide is the river?
The diagram: W 21 m 7 m 15 m Work…
Question 2: Julie wants to know how far it is from her house to the big oak tree. She drew a diagram and labeled it with her known measurements. How far is the tree from her house?
16 ft 24 ft 6 ft 4 ft 5 ft Diagram…. Work…..
?? 3 ft 6 ft 2 ft Question 3 A yardstick casts a 2-ft shadow. At the same time, a tree casts a shadow that is 6 ft long. How tall is the tree?
30 ft ????? 3 ft 18 ft Question 4; A 30 ft building casts a shadow that is 18 ft long. A nearby tree casts a shadow that is 3 ft long. How tall is the tree?
AC = 30 D DC = 20 BE = 4 AB = ? E C A B Question 5 Triangles with triangles…
AC = 24 D DC = ? BE = 8 AB = 4 E C A B Question 6;