# RD Sharma Solutions for Class 9 Maths Chapter 15: Areas of Parallelogram and Triangle

We have learnt about the triangle in the chapter on Triangles and quadrilaterals. But in this chapter, we will learn about how to determine the area of a Parallelogram and a triangle. We know that we can use Heron's formula to determine its area if all the sides are given in triangles.

Area = s(s-a)(s-b)(s-c)

where a, b, c are the sides of the triangle and 's' is the semi-perimeter of the triangle

That formula works for all kinds of triangles. But what if we can find the area of a triangle more simply, it would be a better option and more efficient. To find the area of a triangle via any other method, we have to know about some basic triangle parameters like base and height. For a right-angled triangle, the base is 5 cm. The height is 6 cm. We can find out the area of that triangle using the formula In the case of a parallelogram, we can find out the area of the figure using the base and height. For example, if the height of a parallelogram is 17 cm. The base is 20 cm. then the area of the given parallelogram is

Area= Base x Height, 17 x 20 cm2 = 340 cm2.

In this chapter, some problems will include triangles within a parallelogram. In that case, we have to find out how many triangles are forming the parallelogram. Then we have to determine the area of triangles included in that parallelogram to find out the area of the parallelogram.