NCERT Class 9 Maths Formula CBSE Board Sample Problems Part 11 (For CBSE, ICSE, IAS, NET, NRA 2022)

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11. Heron Formula

Heron Formula
S. noTermDescription
1MensurationIt is branch of mathematics which is concerned about the measurement of length, area, and Volume of plane and Solid figure
2Perimeter(a) The perimeter of plane figure is defined as the length of the boundary

(b) Its units are same as that of length i.e.. . , m, cm, km

3Area(a) The area of the plane figure is the surface enclosed by its boundary

(b) Its unit is square of length unit. i.e.. . ,

Unit Conversion

Unit Conversion
1 Meter10 Decimeter100 centimeter
1 Decimeter10 centimeter100 millimeter
1 Km10 Hectometer100 Decameter
1 Decameter10 meter1000 centimeter
1 square Meter100 square Decimeter10000 square centimeter
1 square Decimeter100 square centimeter10000 square millimeter
1 Hectare100 square Decameter10000 square meter
1 square myraimeter100 square kilometer square meter

Perimeter and Area of Different Figure

Perimeter and Area of Different Figure
1Right angle triangle

Base = b, Height = h

Hypotenuse = d

Height = h

2Isosceles right angled triangle Equal side = a

Height = a

3Any triangle of sides a, b c


This is called Heron՚s formula (sometimes called Hero՚s formula) is named after Hero of Alexandria

4Square Side = a
5Rectangle of Length and breadth L and B respectivelyA = LX B
6Parallelograms Two sides are given as a and bA = Base X height

When the diagonal is also given, say d


W here

7Rhombus Diagonal d1 and d2 are given


(a) All the sides are given a, b, c, d

(b) Both the diagonal are perpendicular to each other

(c) When a diagonal and perpendicular to diagonal are given where d is diagonal and and are perpendicular to that

(a) (a)



Where and are the diagonal


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