List

Perimeter and Area

Salinon
problem

Salinon

Age
14 to 16
Challenge level
filled star empty star empty star
This shape comprises four semi-circles. What is the relationship between the area of the shaded region and the area of the circle on AB as diameter?
Curvy areas
problem

Curvy areas

Age
14 to 16
Challenge level
filled star empty star empty star
Have a go at creating these images based on circles. What do you notice about the areas of the different sections?
Track design
problem

Track design

Age
14 to 16
Challenge level
filled star empty star empty star
Where should runners start the 200m race so that they have all run the same distance by the finish?
Arclets
problem

Arclets

Age
14 to 16
Challenge level
filled star filled star empty star
Each of the following shapes is made from arcs of a circle of radius r. What is the perimeter of a shape with 3, 4, 5 and n "nodes".
Triangles and petals
problem

Triangles and petals

Age
14 to 16
Challenge level
filled star filled star empty star
An equilateral triangle rotates around regular polygons and produces an outline like a flower. What are the perimeters of the different flowers?