NCERT Class 9 Maths Formula CBSE Board Sample Problems Part 11

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11. Heron Formula

Heron Formula

S.no

Term

Description

1

Mensuration

It is branch of mathematics which ¡s concerned about the measurement of length ,area and Volume of plane and Solid figure

2

Perimeter

a)The perimeter of plane figure is defined as the length of the boundary

b)It units is same as that of length i.e. m ,cm, km

3

Area

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

b) It unit is square of length unit. i.e.

Unit Conversion

Unit Conversion

1 Meter

10 Decimeter

100 centimeter

1 Decimeter

10 centimeter

100 millimeter

1 Km

10 Hectometer

100 Decameter

1 Decameter

10 meter

1000 centimeter

1 square Meter

100 square Decimeter

10000 square centimeter

1 square Decimeter

100 square centimeter

10000 square millimeter

1 Hectare

100 square Decameter

10000 square meter

1 square myraimeter

100 square kilometer

square meter

Perimeter and Area of Different Figure

Perimeter and Area of Different Figure

N

Shape

Perimeter/height

Area

1

Right angle triangle

Base =b, Height =h

Hypotenuse=d

Height =h

2

Isosceles right angled triangle Equal side =a

Height=a

3

Any triangle of sides a, b c

Where

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

4

Square Side =a

P=4a

5

Rectangle of Length and breadth L and B respectively

A=LX B

6

Parallelograms Two sides are given as a and b

A= Base X height

When the diagonal is also given ,say d

Then

W here

7

Rhombus Diagonal d1 and d2 are given

8

Quadrilateral

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

b)

Where and are the diagonal

c)