RD Sharma Class 8 Solutions Chapter 20 - Area of Trapezium and Polygon (Ex 20.2) Exercise 20.2

In this chapter, we learn about the area of a trapezium and polygon. In Section 20.16, you can find out how to calculate the area of a triangle given its height. The concept is very important from an exam point of view so make sure that you understand it well! You need to be able to work with trapezium and polygons to be able to do well in your exams.

In this chapter, we also learn about the area of a trapezium and polygon, including how to find out an unknown length or width given some other line segment with the same endpoints as yours (and vice versa). Make sure you keep all these formulas on hand while answering questions! You can use them for any shape, so they are very important. The units that were used in the question will help you determine what type of calculation is needed: if it’s centimetres, then one side would need to be multiplied by 100; however if it was kilometres, you would need to multiply our answer by 1000 instead. If there was some other line segment with the same endpoints as your given one, it would create two triangles sharing those vertices along with their respective sides. Finally, remember that the area of a trapezium or polygon must lie within the range –10000<=Area<= 10000.

The Concept of the Area of a Trapezium and Polygon

It is very important from an exam point of view. So, make sure you understand it well.

The first concept of the area of a trapezium and polygon is the area of a trapezium that is the sum of two bases times the height.

The second concept to remember is that for a polygon, you can choose to use either the width or length as your base and then multiply it by the number of sides.

The third concept to remember is that the area of a trapezium and the area of a polygon are both positive.

The fourth concept to keep in mind is that you can use this formula for all polygons, no matter how many sides they have.

The fifth important thing to know about a trapezium or a polygon is that if one side has been doubled, then its corresponding diagonal must be used twice (this also applies for finding the perimeter).

The sixth thing you need to remember when trying to find out an unknown length or width of either shape is that if there was some other line segment with the same endpoints as your given one, it would create two triangles sharing those vertices along with their respective sides.

The seventh concept to remember is that if you are trying to find out the area of a trapezium or polygon, then make sure your answer lies within the range –10000 <= Area <= 10000.

The eighth thing about finding an area for either shape is to check what units they used in their question (for example, both sides could be centimetres). The ninth and final main idea when it comes to learning how to work with trapeziums and polygons is that don’t forget all the formulas; regular shapes like this can often appear on exams!

So, these are the eight main points that you need to remember when it comes to working with trapeziums and polygons. Make sure you go over them a few times so that the concepts sink in. Once you have mastered these, finding an area for any shape will be a breeze!