Isosceles and Equilateral Triangles

Front

What is an isosceles triangle?

Back

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

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 the sum of the interior angles of a triangle?

Back

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

Front

If two angles of a triangle are equal, what can be said about the sides opposite those angles?

Back

The sides opposite the equal angles are also equal in length.

Front

What is the vertex angle in an isosceles triangle?

Back

The vertex angle in an isosceles triangle is the angle formed by the two equal sides.

Front

How do you find the measure of the vertex angle in an isosceles triangle if the base angles are known?

Back

The measure of the vertex angle can be found using the formula: Vertex Angle = 180° - 2(Base Angle).

Front

What are remote interior angles in relation to exterior angles?

Back

Remote interior angles are the two interior angles of a triangle that are not adjacent to a given exterior angle.

Front

What is the relationship between the sides and angles in a triangle?

Back

In a triangle, the larger the angle, the longer the side opposite that angle.

Front

What is the base angle in an isosceles triangle?

Back

The base angles in an isosceles triangle are the angles opposite the two equal sides.

Front

If one angle of a triangle measures 90°, what type of triangle is it?

Back

If one angle of a triangle measures 90°, it is a right triangle.