2. Trying Triangles By Jan, Marcia, Carole, and Donna

3. 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.

4. Types of Triangles Equilateral triangle – all sides are of an equal length.

5. Isosceles triangle – two sides are of equal length.

6. Scalene triangle - all sides have different lengths.

7. Euclid Elementary facts about triangles were presented by Euclid in books 1 – 4 of his Elements around 300 BCE.

8. 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 one of your triangles for me? Can you pick out a triangle from among the shapes on the board? How are the triangles like the other objects? How are they different? If my eyes were closed, how would you describe the triangle so that I would know what it looks like? Would you count the number of sides of each of your shapes for me so we can see if they are triangles?

9. How many triangles can you find in the classroom without leaving your space? Can you describe the location of the triangles so that your classmates can find them? What are some words you might use to describe the triangles found in the room?

10. 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

11. 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!

12. 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

13. 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

14. Four Triangles Puzzle Santa had lots of squares of wood left over from cutting out windows in dolls' houses. He doesn't like to waste wood so he asked his elves to think of something to use the squares for. One clever little elf thought of cutting the squares into four triangles to make a puzzle. Cut four triangles from a square as shown in the picture. How many different shapes can you make by fitting the four triangles back together? You can only fit long sides to long sides and short sides to short sides. http://nrich.maths.org/public/viewer.php?obj_id=141&par t=index&refpage=leg.php

15. http://nrich.maths.org/public/viewer.php?obj_id=2342 &part=index&refpage=leg.php Click on this link for more triangle fun.

16. Additional Website Activities http://nrich.maths.org/public/viewer.php?obj_id=967&part=index &refpage=leg.phphttp://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.phphttp://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=inde x&refpage=leg.phphttp://nrich.maths.org/public/viewer.php?obj_id=2852&part=inde x&refpage=leg.php http://pbskids.org/sagwa/games/tangrams/index.html

17. Good job!!!