Exterior Angle Sum of Triangles

Which of the following angles are remote interior angles to angle d? 

• Angle a and Angle b
• Angle b and Angle c
• Angle a and Angle c
• Angle a and Angle b and Angle c

Tags

CCSS.8.G.A.5

Which of the following terms best describes Angle d? (remember that it's outside)

• Remote interior angle
• Corresponding angle
• Exterior angle
• Interior angle

Tags

CCSS.8.G.A.5

What is the measure of angle b?

• 36^o
• 56^o
• 63^o
• 117^o

Answer explanation

Method 1: Use the exterior angle theorem. You have the exterior angle (117°), so if you take away one remote interior angle (81°), you'll get the other one.

117 - 81 = b

Method 2: Find angle a since its a linear pair (180-117 = 63°). Then since angles in a triangle add to 180, you know 81° + 63° + b = 180, and you can solve for b.

Tags

CCSS.8.G.A.5

Find the measure of the indicated angle. (remember that the sum of interior angles is equal to 180 degrees)

• 95°

• 85°

• 35°

• 45°

Answer explanation

Since all the angles add to 180, you can subtract 110 and 25 from 180.

180 - 110 - 25 = ___

Tags

CCSS.8.G.A.5

Find the value of x by using the exterior angle theorem.

• A
• B
• C
• D

Answer explanation

Use the exterior angle theorem to set up the equation shown in the picture (12x + 9x = 105).

Combine like terms (21x = 105).

Divide both sides by 21.

x = 5

Tags

CCSS.8.G.A.5

Find the value of x by using the exterior angle theorem.

• A
• B
• C
• D

Answer explanation

Use the exterior angle theorem to set up the equation shown to the left (3x+19 + 5x = 115).

Combine like terms to get

8x + 19 = 115

Subtract 19 from both sides.

8x = 96

Dived both sides by 8.

x = 12

Tags

CCSS.8.G.A.5

Find the measure of the indicated angle. 

• 145°

• 113°

• 102°

• 78°

Answer explanation

Tags

CCSS.8.G.A.5

Find the measure of angle A.

• 44^o
• 96^o
• -14^o
• 63^o

Answer explanation

Tags

CCSS.8.G.A.5

Find the measure of the indicated angle. 

• 34°

• 46°

• 62°

• 36°

Answer explanation

Tags

CCSS.8.G.A.5

What is the measure of angle A in the triangle?

• 116°

• 25°

• 62°

• 54°

Answer explanation

Tags

CCSS.8.G.A.5