Triangle Sum Theorem and Exterior Angle Theorem

Front

What is the Triangle Sum Theorem?

Back

The Triangle Sum Theorem states that the sum of the interior angles of a triangle is always 180 degrees.

Front

What is the Exterior Angle Theorem?

Back

The Exterior Angle Theorem states that the measure of an exterior angle of a triangle is equal to the sum of the measures of the two non-adjacent interior angles.

Front

What are the conditions for three lengths to form a triangle?

Back

The lengths must satisfy the Triangle Inequality Theorem: the sum of the lengths of any two sides must be greater than the length of the third side.

Front

If the sides of a triangle are 2 cm, 4 cm, and 7 cm, does it form a triangle?

Back

No, because 2 + 4 is not greater than 7.

Front

If the sides of a triangle are 43 cm, 10 cm, and 40 cm, does it form a triangle?

Back

Yes, because 43 + 10 > 40, 43 + 40 > 10, and 10 + 40 > 43.

Front

If the sides of a triangle are 5 cm, 10 cm, and 7 cm, does it form a triangle?

Back

Yes, because 5 + 7 > 10, 5 + 10 > 7, and 7 + 10 > 5.

Front

If the sides of a triangle are 50 cm, 10 cm, and 17 cm, does it form a triangle?

Back

No, because 10 + 17 is not greater than 50.

Front

What is the formula to find the measure of an exterior angle?

Back

The measure of an exterior angle is equal to the sum of the two opposite interior angles.

Front

What is the relationship between the angles in a triangle?

Back

The sum of the three interior angles in a triangle is always 180 degrees.

Front

How do you determine if a triangle is valid using side lengths?

Back

Check if the sum of any two sides is greater than the third side for all combinations.