Angles in Triangles

What is the sum of the angle measures in a triangle?

• 90°

• 180°

• 360°

• 270°

If two angles of a triangle are 30° and 70°, what is the measure of the third angle?

• 60°

• 70°

• 80°

• 90°

What is the definition of an obtuse angle?

• An obtuse angle is an angle that measures more than 90° but less than 180°.

• An obtuse angle is an angle that measures exactly 90°.

• An obtuse angle is an angle that measures less than 90°.

• An obtuse angle is an angle that measures more than 180°.

Which of the following sets do NOT make a triangle: 60, 60, 60; 55, 65, 45; 45, 90, 45; 75, 40, 65?

• 60, 60, 60

• 45, 90, 45

• 75, 40, 65

• 55, 65, 45

What is the relationship between the angles in an isosceles triangle?

• The angles opposite the equal sides are equal.

• All angles are equal in an isosceles triangle.

• The angles opposite the unequal sides are equal.

• The sum of the angles is always 180 degrees.

What is the formula to find the measure of an interior angle of a regular polygon?

• (n-2) × 180° / n

• (n+2) × 180° / n

• (n-2) × 90° / n

• (n-3) × 180° / n

Find the measure of the missing angle if one angle is 60° and another is 90°. What is the missing angle?

• 30°

• 45°

• 60°

• 75°

What is the measure of an angle in a triangle if the other two angles are 36° and 54°?

• 80°

• 90°

• 100°

• 110°

What is the definition of a triangle?

• A polygon with four edges and four vertices.

• A polygon with three edges and three vertices.

• A shape with no edges or vertices.

• A polygon with five edges and five vertices.

If one angle of a triangle is 110°, what is the maximum possible measure of the other two angles?

• 60° each

• 70° each

• 80° each

• 90° each