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.

Tags

CCSS.4.G.A.2

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°.

Tags

CCSS.4.G.A.2

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°.

Tags

CCSS.8.G.A.5

Front

If two angles of a triangle are equal, what can be said about the triangle?

Back

The triangle is isosceles.

Tags

CCSS.2.G.A.1

Front

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

Back

The vertex angle measures 100°.

Tags

CCSS.8.G.A.5

Front

How do you find the perimeter of an equilateral triangle?

Back

The perimeter of an equilateral triangle is found by multiplying the length of one side by 3.

Tags

CCSS.3.MD.D.8

Front

If the side length of an equilateral triangle is 24, what is its perimeter?

Back

The perimeter is 72 (24 x 3).

Tags

CCSS.3.MD.D.8

Front

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

Back

All angles in an equilateral triangle are equal, each measuring 60°.

Tags

CCSS.HSG.CO.C.11

Front

In triangle ABC, if angle A = 45° and angle B = 45°, what is angle C?

Back

Angle C = 90°.

Tags

CCSS.8.G.A.5

Front

What is the formula for the area of a triangle?

Back

Area = 1/2 * base * height.

Tags

CCSS.6.G.A.1