#5.1 Angles of Triangles

Front

What is a triangle classified by its sides?

Back

Triangles can be classified as Equilateral (all sides equal), Isosceles (two sides equal), or Scalene (no sides equal).

Front

What is a triangle classified by its angles?

Back

Triangles can be classified as Acute (all angles less than 90°), Right (one angle equal to 90°), or Obtuse (one angle greater than 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 one angle of a triangle is 90°, what type of triangle is it?

Back

It is a Right triangle.

Front

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

Back

Subtract the sum of the known angles from 180°.

Front

What is an Isosceles triangle?

Back

An Isosceles triangle has at least two sides of equal length and the angles opposite those sides are equal.

Front

What is a Scalene triangle?

Back

A Scalene triangle has all sides of different lengths and all angles of different measures.

Front

What is an Acute triangle?

Back

An Acute triangle has all angles measuring less than 90°.

Front

What is an Obtuse triangle?

Back

An Obtuse triangle has one angle that measures more than 90°.

Front

If two angles of a triangle are 40° and 60°, what is the measure of the third angle?

Back

The third angle measures 80° (180° - 40° - 60°).