Finding Missing Angles in Triangles

Front

What is the sum of the angles in a triangle?

Back

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

Front

If one angle in a triangle is 90 degrees, what type of triangle is it?

Back

It is a right triangle.

Front

What is the formula to find the missing angle in a triangle?

Back

To find the missing angle, subtract the sum of the known angles from 180 degrees.

Front

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

Back

The third angle is 70 degrees (180 - 50 - 60 = 70).

Front

What do you call an angle that is less than 90 degrees?

Back

An acute angle.

Front

What do you call an angle that is exactly 90 degrees?

Back

A right angle.

Front

What do you call an angle that is greater than 90 degrees but less than 180 degrees?

Back

An obtuse angle.

Front

In triangle ABC, if angle A = 25 degrees and angle B = 75 degrees, what is angle C?

Back

Angle C is 80 degrees (180 - 25 - 75 = 80).

Front

If angle A = 30 degrees and angle B = x degrees, what is the value of x if angle C = 90 degrees?

Back

x = 60 degrees (180 - 30 - 90 = 60).

Front

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

Back

In an isosceles triangle, the angles opposite the equal sides are equal.