4-6 Equilateral and Isosceles Triangles

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 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 the sum of the interior angles of a triangle?

Back

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

Front

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

Back

If two angles of a triangle are equal, it is an isosceles triangle.

Front

How do you find the height of an equilateral triangle?

Back

Front

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

Back

In an isosceles triangle, the angles opposite the equal sides are also equal.

Front

What is the formula for the area of a triangle?

Back

Front

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

Back

The other two angles will each measure 70 degrees, since the sum of the angles must equal 180 degrees.

Front

What is the Pythagorean theorem?

Back

Front

How do you determine if a triangle is equilateral using its side lengths?

Back

A triangle is equilateral if all three of its side lengths are equal.