Isosceles Triangle Theorem

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 the Isosceles Triangle Theorem?

Back

The Isosceles Triangle Theorem states that the angles opposite the equal sides of an isosceles triangle are also equal.

Front

If two sides of a triangle are equal, what can be said about the angles opposite those sides?

Back

The angles opposite the equal sides are equal.

Front

What is the Triangle Sum Theorem?

Back

The Triangle Sum Theorem states that the sum of the interior angles of a triangle is 180°.

Front

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

Back

Each of the other two angles measures 70°.

Front

In an isosceles triangle, if the equal sides are 10 cm each and the base is 8 cm, what is the height of the triangle?

Back

The height can be found using the Pythagorean theorem, resulting in approximately 7.21 cm.

Front

What is the relationship between the base angles of an isosceles triangle?

Back

The base angles of an isosceles triangle are equal.

Front

If the angles of an isosceles triangle are 50°, x°, and x°, what is the value of x?

Back

x = 65°.

Front

How do you find the measure of an angle in an isosceles triangle if you know the measure of the vertex angle?

Back

Subtract the vertex angle from 180° and divide by 2 to find each base angle.

Front

What is the formula for the area of a triangle?

Back

The area A of a triangle can be calculated using the formula A = 1/2 * base * height.