Lesson 12B Bell 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 can be said about the triangle?

Back

The triangle is isosceles.

Front

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

Back

All angles in an equilateral triangle are equal and each measures 60 degrees.

Front

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

Back

To find the measure of an unknown angle, subtract the sum of the known angles from 180 degrees.

Front

What is the base of an isosceles triangle?

Back

The base of an isosceles triangle is the side that is not equal in length to the other two sides.

Front

What is the vertex angle in an isosceles triangle?

Back

The vertex angle is the angle formed by the two equal sides of the isosceles triangle.

Front

If the base angles of an isosceles triangle are 45 degrees, what is the vertex angle?

Back

The vertex angle is 90 degrees.

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.