Illustrative Mathematics - Geometry - Unit 3 - Lesson 15 - Formative Library | Library

In the right triangles shown, the measure of angle ABC is the same as the measure of angle EBD.  ​​​What is the length of side BE?

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In right triangle ABC, angle C is a right angle, AB=13, and BC=5. What is the length of AC?

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In this diagram, lines AC and DE are parallel, and line DC is perpendicular to each of them.
 What is a reasonable estimate for the length of side BE?

\frac{1}{3}

1

\frac{5}{3}

5

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Select all of the right triangles.

Triangle ABC  with AB=30, BC=40, and AC=50

Triangle XYZ  with XY=1, YZ=1, and XZ=2

Triangle EFG  with EF=8, FG=15, and EG=17

Triangle LMN  with LM=7, MN=24, and AC=25

Triangle QRS  with QR=4, RS=5, and QS=6

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Andre says he can find the length of the third side of triangle ABC and it is 13 units. Mai disagrees and thinks that the side length is unknown. Who do you agree with? Show or explain your reasoning.

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In right triangle ABC, altitude CD with length h is drawn to its hypotenuse. We also know AD=8 and DB=2. 
What is the value of h?

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Select the sequence of transformations that would show that triangles ABC and AED are similar. The length of AC  is 6.

Dilate from center A by a scale factor of 4, then reflect over line AC.

Dilate from center A by a scale factor of 2, then reflect over line AC.

Dilate from center A by a scale factor of 2, then rotate 60º around angle A.

Translate by directed line segment DC, then reflect over line AC.

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This lesson is from Illustrative Mathematics. Geometry, Unit 3, Lesson 15. Internet. Available from https://curriculum.illustrativemathematics.org/HS/teachers/2/3/15/index.html ; accessed 29/July/2021.

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