NCERT Class 9 Solutions: Heron's Formula (Chapter 12) Exercise 12.1 Part 2

Herons Formula and its components

Herons Formula

Herons Formula and its components

Q-5 Sides of a triangle are in the ratio of Equation and its perimeter is Equation . Find its area.Solution:

  • Ratio of the sides of the triangle Equation

  • Let the common ratio be Equation then sides are Equation

    Perimeter of the triangle Equation

    • Equation ( Equation )

    • Equation

    • Equation

    Sides of triangle are,

  • Equation ( Equation )

  • Equation ( Equation )

  • Equation ( Equation )

Semi perimeter of triangle(s)

  • Equation

Using heron's formula, area of the triangle

  • Equation

  • Equation

  • Equation

  • Equation

Q-6 An isosceles triangle has perimeter 30 cm and each of the equal sides is 12 cm. Find the area of the triangle.Solution:

  • Length of the equal sides Equation

  • Perimeter of the triangle Equation

  • Length of the third side Equation Equation

  • Semi perimeter of the triangle(s) Equation

  • Using heron's formula, area of the triangle

    • Equation

    • Equation

    • Equation

    • Equation

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