Triangles and Their Properties

Front

What is an acute triangle?

Back

A triangle in which all three interior angles are less than 90°.

Front

What is an obtuse triangle?

Back

A triangle that has one angle greater than 90°.

Front

What is a right triangle?

Back

A triangle that has one angle equal to 90°.

Front

What is an equiangular triangle?

Back

A triangle where all three interior angles are equal (each angle is 60°).

Front

What is an equilateral triangle?

Back

A triangle with all three sides congruent and all angles equal (also equiangular).

Front

What is an isosceles triangle?

Back

A triangle with at least two sides congruent and two equal base angles.

Front

What is a scalene triangle?

Back

A triangle with no sides and no angles congruent.

Front

What is the Triangle Sum Theorem?

Back

The sum of the interior angles of a triangle is always 180°.

Front

What is the Triangle Exterior Angle Theorem?

Back

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 is the Isosceles Triangle Theorem?

Back

If two sides of a triangle are congruent, then the angles opposite those sides are congruent.