Hg
Name: Class 8 STICK TO WALL IN YOUR STUDY AREA
___________________________________________________________________________________________________________________________________
___________________________________________________________________________________________________________________________________
The Hg Classes (8
th
to 12
th
) By: Er Hershit Goyal (B.Tech. IIT BHU), 134-SF, Woodstock Floors, Nirvana Country, Sector 50, GURUGRAM +91 9599697178.
fb.me/thehgclasses linkedin.com/company/the-hg-classes instagram.com/the_hg_classes g.page/the-hg-classes-gurugram thehgclasses.co.in
Mensuration Formulae
2D SHAPES
SQUARE:
RECTANGLE:
TRIANGLE:
a, b, c = sides,
b = base, h = height
Perimeter = a + b + c
Area =
b h
EQUILATERAL TRIANGLE:
a = side
Height =
Perimeter = 3a
Area =
s = length of a side
l = length
w = width or breadth
Perimeter = 4s
Area = s
2
Perimeter = 2 (l + w)
Area = l x w
PARALLELOGRAM:
RHOMBUS:
l = side;
d
1
, d
2
= diagonals
Perimeter = 4 l = 2
Area =
CIRCLE:
TRAPEZIUM:
a, b = parallel sides
h = height
Perimeter = a + b + c + d
Area =
(sum of || sides) h
=
(a+ b) h
b = base,
r = radius
h = height,
d = diameter
a = other side
Perimeter = 2(a + b)
Area = b h
Diameter = 2r
Perimeter = 2πr
Area = πr
2
3D SHAPES
PRISM:
CUBOID:
CUBE:
CYLINDER:
LSA = Base Peri. x H
Volume = Base Area x H
• Cuboid is a
l = length, b = breadth,
h = height
a = length of a side
r = radius of
base, h = height
Rectangular Prism
• Cube is a
Square Prism
• Cylinder is a
Circular Prism,
• Similarly, there are
triangular &
polygonal prisms.
LSA = 2h (l + b)
TSA = 2 (lb + bh + hl)
Volume = l b h
LSA = 4a
2
TSA = 6a
2
V = a
3
CSA = 2 πrh
TSA = 2πr (h + r)
V = πr
2
h
1 m = 100 cm
1 km = 1000 m
1 m
2
= 100 x 100 cm
2
= 10
4
cm
2
1 m
3
= 100 x 100 x 100 cm
3
= 10
6
cm
3
= 1000 L = 1 KL
1 L = 1000 cm
3
or 1000 c.c.
