Triangles Galore!

Classification By Angle Acute triangle Obtuse triangle Right triangle

Acute Triangles An acute triangle has only acute angles. What could another combination of angles be for an acute triangle?

Obtuse triangle An obtuse triangle has one obtuse angle. Can a triangle have more than two obtuse angles?

Right Triangle A right triangle has only one right angle. Can a right triangle also be an acute triangle?

180o When you add all the angles of any triangle they add up to 1800. We proved this in yesterdays lab! Tear the corners off of a triangle, connect them together using their smooth sides and see what it makes.

Find the unknown angle then classify it. 60 90 60 60

Classification by Sides Equilateral triangle Isosceles triangle Scalene triangle

What does it mean to be congruent? Sides of a shape are congruent if they are the same length. You can use tick marks to show congruent sides.

Scalene Triangle A scalene triangle has no congruent sides. If a triangle has no congruent sides, what do you know about it’s angle measurements?

Isosceles Triangle An isosceles triangle has at least two congruent sides. Can a right triangle also be isosceles?

Equilateral Triangle An equilateral triangle has three congruent sides. Draw an example of an equilateral triangle and label the side measurements.

Let’s Classify! Classify the triangles by there angles and sides. 1. 2. 3.

Try this one! The perimeter of the triangle is 24 cm. Classify the triangle. 8 8

Try this one! The perimeter of the triangle is 30 ft. Classify the triangle. 6ft. 12 ft.