Classifying and Missing Angles in a Triangle

Front

What is the name of this triangle?

Back

The triangle is named \( \Delta ABC \).

Front

What are the properties of an equilateral triangle?

Back

An equilateral triangle has all congruent sides.

Front

What are the properties of an isosceles triangle?

Back

An isosceles triangle has two congruent sides.

Front

What is an acute triangle?

Back

An acute triangle has all angles that are less than 90°.

Front

What is a right triangle?

Back

A right triangle has one angle that is exactly 90°.

Front

What is an obtuse triangle?

Back

An obtuse triangle has one angle that is greater than 90°.

Front

How do you find the missing angle in a triangle?

Back

The sum of the angles in a triangle is always 180°. Subtract the known angles from 180° to find the missing angle.

Front

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

Back

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

Front

What is the formula for the sum of angles in a triangle?

Back

The sum of the angles in a triangle is given by: \( A + B + C = 180° \).

Front

What is the definition of congruent angles?

Back

Congruent angles are angles that have the same measure.