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 degrees.

Front

If two angles of a triangle are equal, what type of triangle is it?

Back

It is an isosceles triangle.

Front

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

Back

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

Front

In an isosceles triangle, if the base angles are 40°, what is the vertex angle?

Back

The vertex angle is 100°.

Front

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

Back

Subtract the sum of the known angles from 180°.

Front

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

Back

In an equilateral triangle, all sides are equal, and all angles are equal to 60°.

Front

If one angle of an isosceles triangle is 80°, what are the measures of the other two angles?

Back

The other two angles are each 50°.

Front

What is the formula for the area of a triangle?

Back

The area of a triangle is given by the formula: Area = 1/2 * base * height.

Front

If the lengths of the two equal sides of an isosceles triangle are 10 cm, what is the minimum length of the base?

Back

The minimum length of the base must be greater than 0 cm and less than 20 cm (the sum of the lengths of the two equal sides).