Exterior Angles of Triangles

This video tutorial explains how to find the unknown exterior angle of a triangle using the exterior angle theorem. The theorem states that the exterior angle is equal to the sum of the two opposite interior angles. The video includes three examples demonstrating this concept, with calculations showing how to apply the theorem to find the exterior angle. The tutorial concludes with a summary of the theorem's application.

What is the main topic discussed in this video?

• Finding the area of a triangle

• Calculating the perimeter of a triangle

• Finding the unknown exterior angle of a triangle

• Understanding the properties of a square

According to the theorem, the exterior angle of a triangle is equal to:

• The difference between two interior angles

• Twice the largest interior angle

• The sum of the two interior opposite angles

• The sum of all interior angles

In the first example, what are the given interior angles?

• 50 and 70 degrees

• 60 and 60 degrees

• 45 and 75 degrees

• 65 and 45 degrees

What is the calculated exterior angle in the first example?

• 130 degrees

• 120 degrees

• 140 degrees

• 110 degrees

In the second example, what are the given interior angles?

• 60 and 60 degrees

• 65 and 45 degrees

• 50 and 70 degrees

• 45 and 75 degrees

What is the calculated exterior angle in the second example?

• 140 degrees

• 110 degrees

• 120 degrees

• 130 degrees

In the third example, what are the given interior angles?

• 65 and 45 degrees

• 45 and 75 degrees

• 50 and 70 degrees

• 60 and 60 degrees

What is the calculated exterior angle in the third example?

• 140 degrees

• 130 degrees

• 120 degrees

• 110 degrees

Which theorem is used to find the exterior angle of a triangle?

• Angle bisector theorem

• Exterior angle theorem

• Pythagorean theorem

• Triangle inequality theorem

What is the sum of the interior angles of a triangle?

• 270 degrees

• 180 degrees

• 360 degrees

• 90 degrees