Triangles - Isosceles & Equilateral

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 to 60°.

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°.

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 also equal.

Front

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

Back

The base angles are each 70°.

Front

How do you find the height of an isosceles triangle?

Back

The height can be found by drawing a perpendicular line from the vertex to the base, creating two right triangles.

Front

What is the Pythagorean theorem?

Back

In a right triangle, the square of the length of the hypotenuse is equal to the sum of the squares of the lengths of the other two sides (a² + b² = c²).

Front

If the sides of an equilateral triangle are 6 cm, what is the perimeter?

Back

The perimeter is 18 cm (6 cm + 6 cm + 6 cm).

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

In triangle ABC, if angle A = 60° and angle B = 60°, what is angle C?

Back

Angle C is 60° (since the sum of angles in a triangle is 180°).