Isosceles and Equilateral Triangles

Front

What is an isosceles triangle?

Back

A triangle with at least two equal sides.

Front

What is an equilateral triangle?

Back

A triangle with all three sides of equal length.

Front

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

Back

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.

Front

What is the measure of each angle in an equilateral triangle?

Back

60 degrees.

Front

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

Back

Each base angle measures 70 degrees.

Front

How do you find the height of an equilateral triangle?

Back

Use the formula: height = (sqrt(3)/2) * side length.

Front

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

Back

The angles opposite the equal sides are equal.

Front

If the length of one side of an equilateral triangle is 12, what is the perimeter?

Back

The perimeter is 36 (12 + 12 + 12).

Front

What is the formula for the area of a triangle?

Back

Area = 1/2 * base * height.