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 and 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

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

Back

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

Front

If one base angle of an isosceles triangle is 40°, what is the vertex angle?

Back

The vertex angle is 100°.

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

How do you calculate the perimeter of an equilateral triangle?

Back

The perimeter of an equilateral triangle can be calculated using the formula: Perimeter = 3 × side length.

Front

If the side length of an equilateral triangle is 24, what is its perimeter?

Back

The perimeter is 72.

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.

Front

If triangle ABC is equilateral, what is the measure of each angle?

Back

Each angle measures 60°.

Front

What is the measure of angle 2 if angle 1 is 50° in a triangle?

Back

Angle 2 is 50°.