CBSE Class 8 Maths Important Formulas
Many students consider mathematics as a scary subject and math formulas are often difficult to remember when you don’t understand them well. The negative approach towards any subjects will make a student reluctant to study that particular subject.Usually students feel jittery during the exam time and they fail to give their best shot. To make things easier and guide through different concepts in Maths, we will discuss the important math formulas for class 8 here.
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Algebraic Expansions:
13. (x – y – z)^{2} = x^{2} + y^{2} + z^{2} – 2xy + 2yz – 2xz
Temperature Conversions :
ºC = 5959 ( ºF – 32 ) ºF = 9595 ( ºC + 32 )
Simple Interest = PTR100PTR100
Pythagorean Theorem:
a^{2 }+ b^{2} = c^{2}
^{ }
Power law: (a^{m})^{n} = a^{mn}
Geometrical Formula:
Sl.No  Figure  Formula for surface area  Formula for volume 
1  Rectangular Prism 
SA = 2ab+2bc+2ca sq. units
where a, b,c are the sides of the cube.

V = abc cubic units 
2  Cylinder 
SA = 2πrh sq. units
TSA = 2πr(h+r) sq. units
r =radius of the cylinder
h – height of the cylinder

V = πr^{2}h cubic units 
3  Cube 
SA = 6a^{2} sq. units
a = sides of the cube

V = a^{3} cubic units 
4  Sphere 
SA = 4πr^{2} sq. units
r = radius of the sphere

V = 4343πr^{3 } cubic units 
5  Ellipsoid 
SA = 4π[(apbp+apcp+bpcp)3]1p4π[(apbp+apcp+bpcp)3]1p
p = 1.6075
a, b, c are semi axis of ellipsoid

V = 4343 π r_{1},r_{2},r_{3} cubic units 
6  Cone  CSA = πr1 sq.units  V = 1313πr^{2}h cubic units 
7  Pyramid 
SA = a+1212*p*l
p = perimeter of pyramid
l = slant height
a = area of the base of the pyramid

V = 1313*a*h cubic units 
8  Torus 
SA = π^{2} * (R^{2} – r^{2})
R:Outer Radius
r: Inner Radius

V = 1414π^{3} (r_{1}+r_{2}) (r_{1}r_{2})^{2} cubic units 
9  Hemisphere 
CSA = 2πr^{2}
TSA = 3πr^{2 }
r = radius

V = 2323 πr^{3} cubic units 
10  Triangle 
SA = s(s−a)(s−b)(s−c)‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾√s(s−a)(s−b)(s−c)
where s is the perimeter of the triangle
a, b, c are the sides of the triangle


11  Rectangle 
A = l*w
L = length
w = width


12  Triangle 
A = 1212bh
b = base h = height


13  Trapezoid  A = 1212 h (b_{1}+b_{2})  
14  Parallelogram  A = bh  
15  Circle  A = πr^{2} r = radius 