NCERT Solutions for Chapter: Heron's Formula, Exercise 3: Exercise

Find the cost of laying grass in a triangular field of sides $50 \mathrm{m}, 65 \mathrm{m}$ and $65 \mathrm{m}$ at the rate of $₹7\text{ per }{\mathrm{m}}^2$.

The triangular side walls of a flyover have been used for advertisements. The sides of the walls are $13 \mathrm{m}, 14 \mathrm{m},$and $15 \mathrm{m}$. The advertisement yield an earning of $₹2000$ per ${\mathrm{m}}^2$ a year. A company hired one of its walls for $6$ months. How much rent did it pay ?

Find the area of a parallelogram given in the figure. Also find the length of the altitude from vertex $\mathrm{A}$ on the side $\mathrm{DC}$.

A field in the form of parallelogram has sides $60 \mathrm{m}$ and $40 \mathrm{m}$ and one of its diagonals is $80 \mathrm{m}$ long. Find the area of parallelogram.

The perimeter of a triangular field is $420 \mathrm{m}$ and its sides are in the ratio $6:7:8$. Find the area of the triangular field.

The sides of a quadrilateral $\mathrm{ABCD}$ are $6 \mathrm{cm},8 \mathrm{cm},12 \mathrm{cm} \mathrm{and} 14 \mathrm{cm}$ (taken in order) respectively, and the angle between the first two sides is a right angle. Find its area.

A rhombus shaped sheet with perimeter $40 \mathrm{cm}$ and one diagonal $12 \mathrm{m}$, is painted on both sides at the rate of $Rs 5 \mathrm{per} {\mathrm{cm}}^2$. Find the cost of painting.

Find the area of the trapezium $PQRS$ with height $PQ$ given in the figure.