NCERT Class 9 Solutions: Heron's Formula (Chapter 12) Exercise 12.2 Part 4
Q-6 An umbrella is made by stitching 10 triangular pieces of cloth of two different colors (see Figure), each piece measuring . How much cloth of each colour is required for the umbrella?
Semi perimeter of each triangle
Area of the triangular piece
Area of triangular piece
Cloth required for each colour
Q-7 A kite in the shape of a square with a diagonal and an isosceles triangle of base each is to be made of three different shades as shown in Figure. How much paper of each shade has been used in it?
We know that the diagonals of a square bisect each other at right angle.
Area of given kite
Thus, (area of kite is
So, area of paper required of each shade
For the section III length of the triangle of sides
Semi perimeter of triangle
Finally, area of the triangular III piece