Triangles I can differentiate between the different types of triangles. Created by: Maggie Howe and Rachel Tankersley Sycamore Elementary 5th grade

Essential Questions: What is a triangle? How do you classify triangles? What is an acute triangle? What is a right triangle? What is an obtuse triangle? What is an isoscelse triangle? What is an equilateral triangle? What is a scalene triangle?

 Triangles are everywhere.  They can be found bracing a bridge.

 Triangles can be found racking up billiard balls.

TTriangles can be classified by sides. OOR TTriangles can be classified by angles.

TRIANGLES BY SIDES  SCALENE  ISOSCELES  EQUILATERAL

SCALENE TRIANGLE  WHEN 3 PEOPLE GET ON THE SCALES TO SEE HOW MUCH THEY WEIGHT, EACH ONE WEIGHS A DIFFERENT AMOUNT. SO…………

 A scalene triangle has no equal sides.  All sides are different lengths.

Isosceles Triangles  Isosceles triangles have 2 equal sides.  The angles opposite the equal sides are also equal. <B = <C AB = AC

Equilateral Triangles  All 3 sides of an equilateral triangle are equal.  Each angle of an equilateral triangle are equal.  Each angle must be 60 degrees.

 Now let’s review.  What kind of triangle has all 3 sides and angles equal?

Equilateral Triangle

 What kind of triangle has all sides a different length ?

SCALENE TRIANGLE

 What kind of triangle has 2 equal sides?

AN ISOSCELES TRIANGLE

TRIANGLES BY ANGLES  Acute  Right  Obtuse

 A right triangle has one 90 degree or RIGHT angle.

Acute triangles 3 angles less than 90 degrees.

OBTUSE TRIANGLE  An obtuse triangle has one obtuse angle.

What type of triangle is this?  Use right, obtuse, or acute.

What type of triangle is this?  Use right, obtuse, or acute.

What type of triangle is this?  Use right, obtuse, or acute.

What type of triangle is this?  Use right, obtuse, or acute.

What type of triangle is this?  Use right, obtuse, or acute.

What type of triangle is this?  Use isosceles, scalene, or equilateral.

What type of triangle is this?  Use isosceles, scalene, or equalateral.

What type of triangle is this?  Use isosceles, scalene, or eqilateral.

What type of triangle is this?  Use isosceles, scalene, or equilateral.

What type of triangle is this?  Use isosceles, scalene, or equilateral.

Which one of these is labeled incorrectly? Right Triangle Equilateral Triangle Scalene Triangle

32 Follow Up Draw an acute triangle. Draw a right triangle. Draw an obtuse triangle. Draw an isoscelse triangle. Draw an equilateral triangle. Draw a scalene triangle. Answer the following questions: Can you have an acute, scalene triangle? Can you have a right isoscelese triangle? Can you have an obtuse, equilateral triangle?