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

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 type of triangle is it?

Back

It is an isosceles triangle.

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 less than 20 cm.

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 one angle of an isosceles triangle measures 40 degrees, what are the measures of the other two angles?

Back

The other two angles each measure 70 degrees.

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 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 base of an isosceles triangle is 8 cm and the height is 5 cm, what is the area?

Back

The area is 20 cm².