Equilateral and Isosceles Triangles

Front

What is an equilateral triangle?

Back

A triangle in which all three sides are of equal length and all three angles are equal, measuring 60 degrees each.

Front

What is an isosceles triangle?

Back

A triangle that has at least two sides of equal length and the angles opposite those sides are also equal.

Front

If two sides of a triangle are congruent, then the angles opposite those sides are congruent. True or False?

Back

True.

Front

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

Back

180 degrees.

Front

In an equilateral triangle, what is the measure of each angle?

Back

60 degrees.

Front

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

Back

Subtract the sum of the known angles from 180 degrees.

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

Back

Each of the other two angles measures 70 degrees.

Front

What is the formula for the area of a triangle?

Back

Area = 1/2 * base * height.

Front

If the base of an isosceles triangle is 10 cm and the height is 8 cm, what is the area?

Back

Area = 1/2 * 10 * 8 = 40 cm².