Mensuration

What this lesson covers

Mensuration is a 8-part O Level Mathematics lesson. Each part makes one point and then hands over to the next, so it can be read in a sitting or picked up again at the part you stopped on. It defines the idea in plain words before using it, works through an example step by step, breaks the topic into its parts and compares them, shows where it is used outside the textbook, names the mistakes that cost marks in an exam, ends with a recap of what to remember.

How it begins

The paper gives you the formulas for the curved surface area of a cone and a sphere, the volume of a sphere, a pyramid and a cone, and the area of a triangle from two sides and an angle. Everything else you must know: rectangle, triangle, parallelogram, trapezium, circle (both circumference and area), and the volumes of prisms and cylinders.

The 8 parts

1. Which formulas you are given, and which you are not
2. Sectors: work out the fraction, then take it
3. Solids: three worked problems
4. Surface area: count the faces
5. Similar shapes in mensuration
6. Where marks go
7. What to remember
8. Watch one worked through