Mensuration (Class 10)

Now, 2nd March is not far away and you must be prepared for the D day. Your syllabus is divided in  six sections Algebra, Geometry, Mensuration, Trigonometry, Coordinate Geometry and Probability. Out of these, each of Algebra and Mensuration contribute 20 marks which means 50% of total marks are covered by these two sections.

If we talk about Mensuration,  here are only two chapters in this section such as “Areas Related to Circles” and “Surface Areas and Volumes”. Both of these chapters come with different varieties of questions, so they need to be taken very seriously.

Few important things which are needed to be taken care of to score well in Mensuration are as follows:

1. Write down all the formulae on a sheet and paste it on your study table to learn all of them by heart.
2. Students find it difficult to find total or curved surface area of combination of solids, so keep it clear in mind that we find the area of the corresponding (curved or whole) surface which can be touched or painted.

For example, let us consider the given solid



This solid is made up of a cube and a hemisphere.

CSA of the solid = CSA of hemisphere
TSA of this solid = TSA of cube + CSA of hemisphere – Area of base of hemisphere
Here, we have subtracted area of base as it is not visible to us and it get added in the area

3. While converting one solid to another remember that the volume of both the solids remain same. So, by equating the volume we can find the dimensions asked in question.
4. Always draw figure in the solution. Do proper labelling as it helps you while calculating area and volume.
5. Take care of values when conversion is being done between two units.
6. To check the area of segment calculated by you is correct or not, you can apply the following formula.

Area of segment =

{ } x2

7. If it is asked to calculate area of sector or segment, you have to find area of minor sector and major segment.
8. Write correct unit in solution. In area, it should always be unit square and in volume, it should always be unit cube. If angle is asked, always write its unit i.e., degree  after the value.

This section demands concentration. So, stay focussed and cross-check your calculations.

Many students know the concept and apply the correct formulae, but a single calculation mistake can deduct the marks.

Best of Luck!

Team Meritnation