A tennis ball is served from directly above the baseline (assume the ball travels in a straight line). What is the minimum height that the ball can be hit at to ensure it lands in the service area?
How many rectangles can you find in this shape? Which ones are differently sized and which are 'similar'?
If the sides of the triangle in the diagram are 3, 4 and 5, what is the area of the shaded square?
Plex lets you specify a mapping between points and their images. Then you can draw and see the transformed image.