Isosceles and Equilateral Triangles

Front

What is an isosceles triangle?

Back

A triangle with at least two equal sides and two equal angles.

Front

What is an equilateral triangle?

Back

A triangle with all three sides equal and all three angles measuring 60 degrees.

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

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

Back

70 degrees.

Front

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

Back

All sides are equal, and all angles are equal to 60 degrees.

Front

How do you find the height of an isosceles triangle?

Back

Drop a perpendicular from the vertex angle to the base, creating two right triangles.

Front

What is the formula for the area of a triangle?

Back

Area = 1/2 * base * height.

Front

If the length of one side of an equilateral triangle is 6, what is the perimeter?

Back

18 (since perimeter = 3 * side length).

Front

What is the Pythagorean theorem?

Back

In a right triangle, a² + b² = c², where c is the hypotenuse.