Trying TrianglesTrying TrianglesTrying TrianglesTrying TrianglesByBy

Jan, Marcia, Carole, and DonnaJan, Marcia, Carole, and DonnaAdapted ByAdapted By

Suzanne & StephanieSuzanne & Stephanie

Can You Answer These Questions?

• Tell me what a triangle looks like.

• How many sides does every triangle have? Would you count the sides of this triangles for me?

• How are the triangles like the other objects? How are

they different? • Would you count the number of sides on some of the

shapes around the room for me so we can see if they are triangles?

• Do you know the types of triangles?

• Do you know the types of angles that they have?

Triangle• A triangle is one of the basic

shapes of geometry.

• A two-dimensional figure with three vertices and three sides which are straight line segments.

Types of Triangles

GET READY!!!!!

• Two sides are of equal length and they have two equal angles.

Isosceles Triangle

• all sides have different lengths and all angles are different.

Scalene Triangle

Equilateral Triangle• Three sides have equal length and

three angles of equal size (which are all 60 degrees.)

Right Angle• Right Triangles (right-angled triangles)

have one right angle (equal to 90°).

It is possible to have a right isosceles triangle - a triangle with a right angle and two equal sides.

Acute Angel• Acute triangles have all acute angles (angles

less than 90°).

It is possible to have an acute triangle which is also an isosceles triangle - these are called acute isosceles triangles.

Obtuse Angle• Obtuse triangles have one obtuse angle

(angle which is greater than 90°).

It is possible to have a obtuse isosceles triangle - a triangle with an obtuse angle and two equal sides.

Tricky Triangles • How many triangles are

in this drawing?

• Name the different types of triangles you find.

• How many of each type of triangle can you find?

http://nrich.maths.org/public/viewer.php?obj_id=1025&part=index&refpage=leg.php

Find the Triangles

• How many triangles are in this drawing?

• You might have to draw the shape many

times and mark each triangle you find. http://nrich.maths.org/public/viewer.php?obj_id=928&part=index&refpage=leg.php

• Look very carefully!

Heptagon Triangles • How many

different triangles can you find in this shape?

http://nrich.maths.org/public/viewer.php?obj_id=195&part=index&refpage=leg.php

Hiding Triangles

• How many triangles can you find?

• Look very carefully, some are hiding!

http://nrich.maths.org/public/viewer.php?obj_id=138&part=index&refpage=leg.php

THE TRIANGLE SONG

Additional Website Activities

• http://nrich.maths.org/public/viewer.php?obj_id=967&part=index&refpage=leg.php

• http://nrich.maths.org/public/viewer.php?obj_id=2124&part=index&refpage=leg.php

• http://nrich.maths.org/public/viewer.php?obj_id=2852&part=index&refpage=leg.php

Good job!!!