Maths Formulas for Class 9

Maths formulas for Class 9 are provided here for the students who consider Mathematics subject as a nightmare and difficult to understand. This may cause them to feel reluctant and lose interest in their studies. Therefore, to help them understand Maths in a simple way, we have accumulated all the important formulas for the 9th standard Maths subject, which students can easily remember.

The formulas are given here as per the NCERT syllabus for all the topics such as Algebra, Geometry, Polynomials, etc.

Also, read the chapterwise notes and study materials for Class 9 Maths to prepare for your examinations.

Class 9 Math Formulas Tables

When you are clear with the logic behind every formula, solving any kind of problem becomes easier. If you are perfect with all the below-mentioned formulas in Maths for Class 9 are listed chapter-wise, nothing can stop you from scoring maximum marks in the final examination.

Geometry

Geometry Shapes Formulas for Class 9
Geometric Figure Area Perimeter
Rectangle A= l × w

Here, l= length and w= breadth

P = 2 × (l+w )
Triangle A = (1⁄2) × b × h

Here, b= base and h= height

P = a + b + c

Here, a,b,c are the sides of the triangle

Trapezoid A = (1⁄2) × h × (b1+ b2)

Here, b1, b2 are length of parallel sides of trapezoid.

P = a + b + c + d

a,b,c,d are the sides of the trapezoid

Parallelogram A = b × h

Here, b= base and h= height

P = 2 (a+b)

a and b are the sides of the parallelogram

Circle A = π r2

C = 2 π r

Algebra

 Algebraic Identities For Class 9 $$\begin{array}{l}(a+b)^{2}=a^2+2ab+b^{2}\end{array}$$ $$\begin{array}{l}(a-b)^{2}=a^{2}-2ab+b^{2}\end{array}$$ $$\begin{array}{l}\left (a + b \right ) \left (a – b \right ) = a^{2} – b^{2}\end{array}$$ $$\begin{array}{l}\left (x + a \right )\left (x + b \right ) = x^{2} + \left (a + b \right )x + ab\end{array}$$ $$\begin{array}{l}\left (x + a \right )\left (x – b \right ) = x^{2} + \left (a – b \right )x – ab\end{array}$$ $$\begin{array}{l}\left (x – a \right )\left (x + b \right ) = x^{2} + \left (b – a \right )x – ab\end{array}$$ $$\begin{array}{l}\left (x – a \right )\left (x – b \right ) = x^{2} – \left (a + b \right )x + ab\end{array}$$ $$\begin{array}{l}\left (a + b \right )^{3} = a^{3} + b^{3} + 3ab\left (a + b \right )\end{array}$$ $$\begin{array}{l}\left (a – b \right )^{3} = a^{3} – b^{3} – 3ab\left (a – b \right )\end{array}$$ $$\begin{array}{l} (x + y + z)^{2} = x^{2} + y^{2} + z^{2} + 2xy + 2yz + 2xz\end{array}$$ $$\begin{array}{l} (x + y – z)^{2} = x^{2} + y^{2} + z^{2} + 2xy – 2yz – 2xz\end{array}$$ $$\begin{array}{l} (x – y + z)^{2} = x^{2} + y^{2} + z^{2} – 2xy – 2yz + 2xz\end{array}$$ $$\begin{array}{l} (x – y – z)^{2} = x^{2} + y^{2} + z^{2} – 2xy + 2yz – 2xz\end{array}$$ $$\begin{array}{l} x^{3} + y^{3} + z^{3} – 3xyz = (x + y + z)(x^{2} + y^{2} + z^{2} – xy – yz -xz)\end{array}$$ $$\begin{array}{l} x^{2} + y^{2} = \frac{1}{2} \left [(x + y)^{2} + (x – y)^{2} \right ]\end{array}$$ $$\begin{array}{l} (x + a) (x + b) (x + c) = x^{3} + (a + b +c)x^{2} + (ab + bc + ca)x + abc\end{array}$$ $$\begin{array}{l} x^{3} + y^{3} = (x + y) (x^{2} – xy + y^{2})\end{array}$$ $$\begin{array}{l} x^{3} – y^{3} = (x – y) (x^{2} + xy + y^{2})\end{array}$$ $$\begin{array}{l} x^{2} + y^{2} + z^{2} -xy – yz – zx = \frac{1}{2} [(x-y)^{2} + (y-z)^{2} + (z-x)^{2}]\end{array}$$

Surface Area and Volume Formulas for Class 9

Following maths formulas for class 9 are essential to solve mensuration questions.

 Shape Surface Area Volume Cuboid 2(lb + bh +lh) l= length, b=breadth, h=height lbh Cube 6a2 a = side of the cube a3 Cylinder 2πr(h+r) r = radius of circular bases h = height of cylinder πr2h Cone πr(l+r) r=radius of base l=slant height  Also, l2=h2+r2, where h is the height of cone (1/3)πr2h Sphere 4πr2 (4/3)πr3

Heron’s Formula

Heron’s formula for class 9 to find the area of triangles is given as

 $$\begin{array}{l}Area ~of~ triangle~ using~ three~ sides =\sqrt{s(s-a)(s-b)(s-c)}\end{array}$$ Semi-perimeter, s = (a+b+c)/2

Polynomial

 Polynomial Formula for Class 9 $$\begin{array}{l}P(x)=a_{n} x^{n}+a_{n-1} x^{n-1}+a_{n-2} x^{n-2}+\ldots \ldots+a x+a_{0}\end{array}$$

Statistics

Important formulas for Class 9 statistics are listed below:

 Measure of Central Tendency Mean Sum of Observation/Total number of observation = ∑ x/n Median [(n+1)/2]th term [For odd number of observation] Mean of (n/2)th term and (n/2+1)th term [For even number of observation] Mode Value which is repeated maximum time in a data set

Probability Formula for Class 9

 Empirical Probability = Number of trials with expected outcome/Total number of Trials

Class Related Formulas

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