NCERT Solutions for Class 9 Maths Chapter 12 Heron’s Formula in PDF form to free download. All **NCERT Solutions** are in Hindi Medium as well as English Medium and both medium have separate download options are given. Useful formulae based on Mensuration are given below at the end of this page, which may be helpful in solving the questions.

## NCERT Solutions for Class 9 Maths Chapter 12

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### 9 Maths Chapter 12 Heron’s Formula Solutions

#### Hindi Medium and English Medium Solutions

- Class 9 Maths Chapter 12 Exercise 12.1 Solutions
- Study Online Exercise 12.1
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- Class 9 Maths Chapter 12 Exercise 12.2 Solutions
- Study Online Exercise 12.2
**Download Exercise 12.2****Download प्रश्नावली 12.2**

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##### Important Formulae and Terms on Heron’s Formula

- Area of Triangle: The total space inside the boundary of the triangle is known as area of the triangle.
- Area of triangle = ½ × base × height
- Area of equilateral triangle: Let the side of an equilateral triangle be k. Then, area of an equilateral triangle = (√3/4) k². Square units and altitude = (√3/2) k units.
- Area of an isosceles triangle: Let B be the base and S be the equal sides of an isosceles triangle, then area of an isosceles triangle = [B√(4S² – B²)]/2 square units.
- Perimeter: Perimeter of a triangle is equal to the sum of its three sides. It is denoted by 2s, where s is the semi-perimeter of a triangle.
- Heron’s Formula: The formula given by Heron about the area of a triangle is known as Heron’s formula. According to this formula, area of triangle = √[s (s – a)(s – b)(s – c)], where a, b and c are three sides of the triangle and s is the semi-perimeter. This formula is also used for finding the area of quadrilateral. In quadrilateral, we join one diagonal to divide the quadrilateral into two triangles and then find the area of each triangle separately by Heron’s formula.