Combining, splitting and comparing angles
"Look closely and reason carefully," says Ollie. "Combining and splitting shapes can surprise you — explain how you know."
1. Bo joins two identical right-angled triangles in different ways. Name two different shapes he could make, and say how the triangles are arranged for each.
2. A rectangle is cut along one diagonal. Then one of those triangles is cut along its height. How many pieces are there now, and what shapes are they?
3. Label each angle as right, smaller than a right angle, or larger than a right angle, then put them in order from smallest to largest.
4. Ollie says a square always has four right angles, but a four-sided shape with four right angles isn't always a square. Sketch a shape that proves Ollie right, and explain.
5. Using only right-angled triangles, what is the smallest number you need to build a rectangle? What about a larger square? Explain your thinking.