Request a call back

Join NOW to get access to exclusive study material for best results

Class 9 NCERT Solutions Maths Chapter 10 - Heron's Formula

Heron's Formula Exercise Ex. 10.1

Solution 1

Side of traffic signal board = a
Perimeter of traffic signal board = 3  a
By Heron's formula
Perimeter of traffic signal board = 180 cm
Side of traffic signal board
Using equation (1), area of traffic of signal board

Solution 2

We may observe that sides of triangle a, b, c are of 122 m, 22 m, and 120 m respectively
    Perimeter of triangle = (122 + 22 + 120) m
                 2s = 264 m
                   s = 132 m
    By Heron's formula
Rent of 1 m2 area per year = Rs.5000
    Rent of 1 m2 area per month = Rs
    Rent of 1320 m2 area for 3 months 
                            = Rs.(5000  330) = Rs.1650000
    So, company had to pay Rs.1650000.

Solution 3

We may observe that the area to be painted in colour is a triangle, having its sides as 11 m, 6 m, and 15 m.
    Perimeter of such triangle = (11 + 6 + 15) m
                                    2 s = 32 m
                                       s = 16 m
By Heron's formula
    So, the area painted in colour is .

Solution 4

Let third side of triangle be x.
  Perimeter of given triangle = 42 cm
        18 cm + 10 cm + x = 42
                                 x = 14 cm
By Heron's formula

Solution 5

Let the common ratio between the sides of given triangle be x.
So, side of triangle will be 12x, 17x, and 25x.
  Perimeter of this triangle = 540 cm
             12x + 17x + 25x = 540 cm
                         54x = 540 cm
                            x = 10 cm
  Sides of triangle will be 120 cm, 170 cm, and 250 cm.
By Heron's formula
    So, area of this triangle will be 9000 cm2.

Solution 6

Let third side of this triangle be x.
Perimeter of triangle = 30 cm
  12 cm + 12 cm + x = 30 cm
                           x = 6 cm
By Heron's formula
Get Latest Study Material for Academic year 24-25 Click here
×