Triangle Song - YouTube

Triangles

A triangle is a 3-sided polygon. Every triangle has three sides and three angles. When added together, the three angles equal 180°.

Acute Triangles

An acute has three angles that are less

than 90°. Remember AAAA. ALL ANGLES ARE

ACUTE!

Obtuse Triangles An obtuse triangle is a

triangle in which one of the angles is greater than 90° and the other two angles are acute.

One obtuse angle and

Two acute angles

Right Triangles

A right triangle is triangle with an angle of 90°.

One right angle and two acute angles

Scalene Triangles A triangle with

three unequal sides.

The “mean scalene” doesn’t want to get along. All of the sides are different lengths!

Isosceles Triangles

To remember this triangle…..

“eye” …soceles” It will remind me that I have 2 eyes. The “e-l-e-s” at the end is close to how we spell the word eyes.

An isosceles triangle has 2 sides that are the same (equal in length).

It has at least 2 acute angles.

An isosceles triangle is a triangle with two equal sides.

When two sides are the same we call them CONGRUENT.

Equilateral Triangles

An equilateral triangle is a triangle with all three sides of equal length

All the angles will be the same size (acute).

Equilateral you are so fine, all your sides are the same size!

Triangle Quiz

Please complete the following quiz that covers the information that was just presented to you.

Question 1 If a triangle has

three unequal sides it is a ______ triangle.A) ScaleneB) ObtuseC) Isosceles

Answer:A) Scalene

Question 2 A triangle which has

three equal sides is a ______ triangle.A) AcuteB) EquilateralC)Scalene

Answer:C) Equilateral

Question 3 A triangle with (at

least) two equal sides is a ______ triangle.A) ScaleneB) IsoscelesC) Congruent

Answer:B) Isosceles

Question 4

Two triangles that are equal are called ______ trianglesA) Acute B) Obtuse C) Congruent

Answer:C) Congruent

Question 5 A triangle with all

three sides of equal length is a ______ triangle.A) EquilateralB) RightC) Equiangular

Answer:A) Equilateral

Question 6 A triangle with an

angle of 90° is a ______ triangle.A) AcuteB) RightC) Congruent

Answer:B) Right

Question 7 A triangle in which

all three angles are less than 90° is a ______ triangle.A) RightB) AcuteC) Scalene

Answer:B) Acute

Question 8 A triangle in which

one of the angles is greater than 90° is a ______ triangle.A) ObtuseB) IsoscelesC) Acute

Answer:A) Obtuse

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