Flashcard 4.2- Isosceles & 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

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 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

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

Back

In an equilateral triangle, all angles are equal and each measures 60°.

Front

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

Back

To find an unknown angle in a triangle, subtract the sum of the known angles from 180°.

Front

What is the formula for the area of a triangle?

Back

The area of a triangle can be calculated using the formula: Area = 1/2 * base * height.

Front

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

Back

The base angles will each measure 70° because the sum of the angles must equal 180°.

Front

What is the definition of congruent triangles?

Back

Congruent triangles are triangles that are identical in shape and size, meaning all corresponding sides and angles are equal.

Front

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

Back

The perimeter of an equilateral triangle is calculated as: Perimeter = 3 * side length = 3 * 6 cm = 18 cm.