Exploring the Triangle Sum Theorem

The video tutorial introduces angle relationships, focusing on the Triangle Sum Theorem, which states that the interior angles of a triangle add up to 180 degrees. The teacher explains how to calculate a missing angle using this theorem, providing step-by-step examples and practice problems to reinforce the concept.

What is the main topic of today's lesson?

• Circle Theorem

• Quadrilateral Theorem

• Triangle Sum Theorem

• Pythagorean Theorem

Tags

CCSS.8.G.A.5

According to the Triangle Sum Theorem, what is the sum of the interior angles of a triangle?

• 270°

• 180°

• 360°

• 90°

Tags

CCSS.8.G.A.5

If two angles of a triangle are 50° and 60°, what is the measure of the third angle?

• 70°

• 80°

• 90°

• 100°

Tags

CCSS.8.G.A.5

In the first example, what are the measures of the two given angles?

• 150° and 19°

• 140° and 29°

• 160° and 9°

• 169° and 3°

Tags

CCSS.7.G.B.5

What is the measure of the missing angle in the first example?

• 5°

• 8°

• 12°

• 10°

Tags

CCSS.4.MD.C.7

In the second example, what should you do if your answer is incorrect?

• Ignore it

• Ask a friend

• Correct your work

• Move on to the next example

Tags

CCSS.RI.6.5

CCSS.RI.7.5

CCSS.RI.8.3

CCSS.RI.8.5

CCSS.RI.9-10.5

In the third example, what is the measure of the given angle in the right triangle?

• 30°

• 45°

• 60°

• 90°

Tags

CCSS.8.G.A.5

What is the first step in solving for the missing angle in the third example?

• Divide the known angles

• Add the two known angles

• Subtract the known angles from 180°

• Multiply the known angles

Tags

CCSS.7.G.B.5

What should you do after solving for the missing angle in the third example?

• Erase your work

• Glue it into your notebook

• Start a new example

• Ask the teacher for help

Tags

CCSS.8.G.A.5

What is the final step mentioned in the video?

• Take a break

• Glue the work into the notebook

• Ask questions

• Review the lesson