The document Facts That Matter- Heron’s Formula Class 9 Notes | EduRev is a part of the Class 9 Course Mathematics (Maths) Class 9.

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**Facts That Matter **

- Area of a triangle
- Heron’s formula:
- For finding area of a quadrilateral we divide it into various triangles. Then we use Heron’s formula to find the area of the triangles.

**AREA OF TRIANGLES**

We have already learnt that area of a triangle

[altitude corresponding to that side (or height)]

[altitude corresponding to base (or height)]

Thus, area of a triangle

Note:Unit of measurement for area of any plane figure is taken as square metre (m^{2}) or square centimetre (cm^{2}), etc.

**HERON’S FORMULA**

When it is not possible to find the height of the triangle easily and measures of all the three sides are known then we use Heron’s formula, which is given by

Area of a triangle =

where a, b and c are the sides of the triangle and s = semi-perimeter, i.e. half the perimeter of the triangle =**AREA OF AN EQUILATERAL TRIANGLE**

Let the side of the equilateral triangle be ‘a’.

∴

⇒ Area of the triangle

Thus, area of an equilateral triangle

192 videos|230 docs|82 tests

### Test: Heron's Formula- 1

- Test | 25 ques | 25 min
### Ex 12.1 NCERT Solutions- Heron’s Formula

- Doc | 3 pages
### Ex 12.2 NCERT Solutions- Heron’s Formula

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### Application of Heron's Formula in Finding Areas of Quadrilaterals

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### Test: Introduction To Heron's Formula

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### Test: Heron's Formula- 2

- Test | 25 ques | 25 min

- NCERT Textbook- Heron's Formula
- Doc | 11 pages