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.

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 any triangle is always 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 in length.

Front

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

Back

The base angles will each measure 70 degrees.

Front

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

Back

In an equilateral triangle, all sides are equal, and all angles are equal to 60 degrees.

Front

How do you find the length of a side in an isosceles triangle given the base and the height?

Back

Use the Pythagorean theorem: if h is the height and b is half the base, then the length of the equal sides is √(h² + b²).

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.

Front

If the lengths of the sides of a triangle are 5, 5, and 8, what type of triangle is it?

Back

It is an isosceles triangle because two sides are equal.

Front

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

Back

The angles opposite the equal sides are equal.