Equilateral and Isosceles Triangles Assessment

Front

What is an equilateral triangle?

Back

An equilateral triangle is a triangle in which all three sides are of equal length and all three angles are equal, each measuring 60°.

Front

What is an isosceles triangle?

Back

An isosceles triangle is a triangle that has at least two sides of equal length and the angles opposite those sides are equal.

Front

What is the sum of the interior angles of a triangle?

Back

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

Front

If one angle of an isosceles triangle is 88°, what are the measures of the other two angles?

Back

The other two angles are each 46° because the sum of the angles must equal 180°.

Front

In an equilateral triangle, what is the measure of each angle?

Back

Each angle in an equilateral triangle measures 60°.

Front

What are the properties of the sides in an isosceles triangle?

Back

In an isosceles triangle, the two sides that are equal in length are called the legs, and the third side is called the base.

Front

How do you find the measure of an unknown angle in an isosceles triangle?

Back

To find the unknown angle, subtract the sum of the known angles from 180°.

Front

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

Back

The angles opposite the equal sides are equal.

Front

If the base angles of an isosceles triangle are 68°, what is the vertex angle?

Back

The vertex angle is 44° because 180° - (68° + 68°) = 44°.

Front

What is the definition of congruent sides in a triangle?

Back

Congruent sides are sides that are equal in length.