BrightPath
Build a Rectangle from Two Triangles
Name:
Date:
Today I am practising: decomposing and recomposing a rectangle along a diagonal
1
Draw a rectangle on scrap paper. Mark two opposite corners.
2
Connect those corners with a straight diagonal.
3
Count the sides of each part. What shapes are the parts?
4
With adult help, cut on the diagonal and separate the parts.
5
Put the parts together to restore the rectangle. Describe which edges meet.
6
Explain why a diagonal makes two triangles even when the rectangle is long and narrow.
- Use a rectangle large enough to cut and handle.
- Avoid making a crease through side midpoints instead of opposite corners.
- Ask the learner to trace the boundary of each part before naming it.