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.

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 to 60 degrees.

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 degrees.

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

In an isosceles triangle, if the equal sides are each 10 cm, what is the minimum possible length of the base?

Back

The minimum possible length of the base is greater than 0 cm, but can be calculated using the triangle inequality theorem.

Front

What is the triangle inequality theorem?

Back

The triangle inequality theorem states that the sum of the lengths of any two sides of a triangle must be greater than the length of the third side.

Front

How do you find the height of an isosceles triangle?

Back

The height can be found by drawing a perpendicular line from the vertex opposite the base to the midpoint of the base.

Front

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

Back

All angles in an equilateral triangle are equal, each measuring 60 degrees.

Front

If the base of an isosceles triangle is 8 cm and the equal sides are 5 cm each, can this triangle exist?

Back

No, it cannot exist because the sum of the lengths of the two equal sides (5 cm + 5 cm) is not greater than the base (8 cm).

Front

What is a congruence statement in geometry?

Back

A congruence statement indicates that two figures are congruent, meaning they have the same shape and size.