Classifying triangles by angles

How many angles does a triangle have?

• 4

• 3

• 2

Tags

CCSS.2.G.A.1

In 4th grade we focus on these three type of angles that we use to identify types triangles.

• acute, obtuse, right angles

• obtuse, scalene,

  and right angles

• isosceles, scalene, and equilateral

Tags

CCSS.4.G.A.2

What is an acute angle?

• An angle that measures 90°

• An angle that measures more than 90° and less than 180°

• An angle that measures between 0 and 90°

  Always less than 90°

• An angle that measures more than 180°

Tags

CCSS.4.G.A.1

What is an obtuse angle?

• An angle that measures less than 90°

• An angle that measures exactly 90°

• An angle that measures more than 90° and less than 180°

Tags

CCSS.4.G.A.1

What is a right angle?

• A right angle measures exactly 180°

• A right angle measures exactly 90°

• A right angle is always less than 90°

Tags

CCSS.4.G.A.1

An acute triangle has how many acute angles?

• 1

• 2

• 3

• none

Tags

CCSS.4.G.A.2

A right triangle must have...

• 1 angle that equals 90° (right angle).

• more than 3 angles.

• two right angles.

Tags

CCSS.4.G.A.2

What is an obtuse triangle?

• An obtuse triangle has one right angle.

• An obtuse triangle has many obtuse angles.

• An obtuse angle has only one obtuse angle.

Tags

CCSS.4.G.A.2

Based on it's angles, what type of triangle is this?

• acute triangle

• obtuse triangle

• right triangle

• equiangular triangle

Tags

CCSS.4.G.A.2

How do you know this is an acute triangle?

Tags

CCSS.4.G.A.2