Equilateral & Isosceles Triangles Period 8

Front

What is an equilateral triangle?

Back

A triangle with all three sides of equal length and all three angles measuring 60°.

Front

What is an isosceles triangle?

Back

A triangle with at least two sides of equal length and the angles opposite those sides are equal.

Front

How do you classify triangles by angles?

Back

Triangles can be classified as acute (all angles < 90°), right (one angle = 90°), or obtuse (one angle > 90°).

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

Back

The vertex angle is 100°.

Front

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

Back

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

Front

How do you find the length of a side in a triangle?

Back

Use the Pythagorean theorem for right triangles or the law of cosines for other 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.

Front

What is the formula for the area of a triangle?

Back

Area = 1/2 * base * height.

Front

If the lengths of two sides of an isosceles triangle are 8, what is the minimum possible length of the base?

Back

The minimum possible length of the base is 0, but practically it must be greater than 0.