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°.

Front

If an isosceles triangle has a base angle of 40°, what is the vertex angle?

Back

The vertex angle is 100°.

Front

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

Back

The sum of the interior angles of any triangle is always 180°.

Front

In an isosceles triangle, if the two equal sides are each 10 cm, what is the minimum possible length of the base?

Back

The minimum possible length of the base is greater than 0 cm but less than 20 cm.

Front

How do you find the perimeter of an equilateral triangle with side length 's'?

Back

The perimeter P of an equilateral triangle is given by P = 3s.

Front

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

Back

In an isosceles triangle, the angles opposite the equal sides are equal.

Front

If triangle ABC is equilateral with a side length of 24 cm, what is its perimeter?

Back

The perimeter is 72 cm.

Front

What is the formula for the area of an isosceles triangle?

Back

The area A of an isosceles triangle can be calculated using A = (base * height) / 2.

Front

If the base of an isosceles triangle is 8 cm and the height is 5 cm, what is the area?

Back

The area is 20 cm².