IGCSE Maths / Circles, cylinders, cones and spheres

Reverse circle problems

Edexcel International GCSE Maths (4MA1), chapter 12: Circles, cylinders, cones and spheres, specification point 4.9e-f. Part of the full course.

Read the revision notes · IGCSE Maths past papers

Reverse circle problems give you the area or circumference and ask for the radius. Rearrange the formula carefully, then check that your answer is a sensible size.

More lessons in Circles, cylinders, cones and spheres

• Circumference of a circle
• Area of a circle
• Semicircles: perimeter and area
• Compound area with circles
• Arc length of a sector
• Area of a sector
• Perimeter of a sector
• Reverse sector problems
• Volume of a cylinder
• Surface area of a cylinder
• Leaving an answer in terms of pi
• Volume of a cone
• Surface area of a cone
• Volume of a sphere
• Surface area of a sphere
• Hemispheres and compound solids
• Frustums and truncated cones
• Reverse volume and surface area problems