Draw a triangle on a piece of paper, and cut it out.
Can you find a way to cut your triangle into no more than four pieces, and reassemble the pieces to make a rectangle?
Is it always possible, no matter what triangle you start with?
If you don't know where to start, click below to see some prompts that may help you:
Start with an isosceles triangle. How could you make it into a rectangle?
Is there a relationship between the base and height of your triangle, and the base and height of the rectangle?
Draw any triangle, find the midpoints of two of the sides, and join them together. What do you notice?
Once you have joined the midpoints, can you rearrange the pieces to make a parallelogram? Does that help you to create a rectangle?