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6-8 Accelerated 7 Unit 1 Lesson 13

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K-5 Math •6-8 Math 9-12 Math

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Accelerated 6 •Accelerated 7

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Lesson 1 Lesson 2 Lesson 3 Lesson 4 Lesson 5 Lesson 6 Lesson 7 Lesson 8 Lesson 9 Lesson 10 Lesson 11 Lesson 12 •Lesson 13 Lesson 14 Lesson 15 Lesson 16 Lesson 17 Lesson 18

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IM K-5 Math
IM 6-8 Math
IM 9-12 Math

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Unit 1, Lesson 13

Adding the Angles in a Triangle

Accelerated 7

Practice

Problem 1

In triangle \(ABC\), the measure of angle \(A\) is \(40^\circ\).

Give possible measures for angles \(B\) and \(C\) if triangle \(ABC\) is isosceles.
Give possible measures for angles \(B\) and \(C\) if triangle \(ABC\) is right.

to access Practice Problem Solutions.

Problem 2

Lesson 13 Resources

Student Materials

For each set of angles, decide if there is a triangle whose angles have these measures in degrees:

a. 60, 60, 60

b. 90, 90, 45

c. 30, 40, 50

d. 90, 45, 45

e. 120, 30, 30

If you get stuck, consider making a line segment. Then use a protractor to measure angles with the first two angle measures.

to access Practice Problem Solutions.

Problem 3

Angle \(A\) in triangle \(ABC\) is obtuse. Can angle \(B\) or angle \(C\) be obtuse? Explain your reasoning.

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Problem 4

ForLesson 3: Making the Moves

For each pair of polygons, describe the transformation that could be applied to Polygon A to get Polygon B.

to access Practice Problem Solutions.