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Mensuration

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Mensuration

Done by T.V.N.K. Sreevasthav


Introduction
• Mensuration is the branch of geometry
that deals with the measurement of
area, length, or volume in 2D and 3D
shapes. The 2D shapes can be drawn in
a plane like square, rectangle, triangle,
circle, etc. and 3D shapes cannot be
represented in a plane like bricks, ice-
cream cones, football, etc. Mensuration
includes computation using
mathematical formulas and algebraic
equations.
2D-Shapes
• RECTANGLE:- Area- lxb sq.units
Perimeter – 2(l+b) units
• TRIANGLE:- Area - x b x h sq.units

Perimeter – Sum Of All Sides. units


• SQUARE:- Area – a x a sq.units
Perimeter – 4 x a units
• CIRCLE:- Area - sq.units
Some 3D shapes

Cube Cuboid Sphere Cylinder Cone


CUBE
CUBE
A cube is a 3-D solid Some Formulae
shape, which has 6 faces.
A cube is one of the • Surface Area of Cube = 6a2 square units
simplest shapes in three- • Volume of cube = a3 cubic units
dimensional space. All • Lateral Surface Area = 4a2 square units
• Length of Diagonal of Face of the Cube = √2 a units
the six faces of a cube • Length of Diagonal of Cube = √3 a units
are squares
CUBOID
CUBOID
• A cuboid is a three dimensional solid that has 6 Some Formulae
faces (rectangular), 8 vertices and 12 edges. A
cuboid has three dimensions such as length,
width and height. A perfect cuboid is said to be a
cuboid that has integer edges.
• Lateral Surface Area (LSA) = 2h(l + b) sq. units
• Consider Euler’s formula, then the relation • Total surface area TSA = 2( lb + bh + hl ) sq. units
between Faces (F), Vertices (V) and Edges (E) of • Volume = lbh cubic units
a cuboid satisfies the equation: • Perimeter = 4(l + b + h) units
F+V=E+2 • Diagonal = √(l^2 + b^2 + h^2) units
SPHER
E
SPHERE
A sphere is three dimensional,
geometrical shape, that has all its Some Formula
surface points equidistant from a
common point. The distance • Surface Area = Square units
between the surface and the common • Volume = cubic units
point is the radius and the common
point is called center of sphere.
HEMI -
SPHERE
Hemi-Sphere

The word hemisphere can be separated into Some Formulae


hemi, which denotes half, and sphere,
which refers to the geometrical 3D shape in • Curved surface area of a hemisphere = 2
mathematics. Consequently, a hemisphere • Area of base =
is a 3D geometric object that is made up of • Total Surface Area = 3
half of a sphere, with one side being flat
• Volume of hemisphere =
and the other being a bowl-like shape.
CYLINDER
CYLINDER
A cylinder is a three-dimensional solid that Some Formulae
holds two parallel bases joined by a curved
surface, at a fixed distance. These bases are • Curved Surface Area = 2πrh square units
• Total surface area = 2πr(r+h) square units
normally circular in shape and the center of • Volume of the Cylinder = πr2h cubic units
the two bases are joined by a line segment,
which is called the axis. The perpendicular
distance between the bases is the height, “h”
and the distance from the axis to the outer
surface is the radius “r” of the cylinder.
CONE
Cone
A pyramid which has a circular Some Formulae

cross-section, unlike pyramid • Slant Height = √(r2+h2) units


which has a triangular cross- • Volume = ⅓ πr2h cubic units
• Total Surface Area = πr(l + r) sq. units
section. These cones are also
stated as a circular cone.
Some Questions on
Mensuration
1. 1. A circle has a radius of 21 cm. Find its circumference and
area. (Use π = 22/7).
2. If one side of a square is 4 cm, then what will be its area
and perimeter?
3. If a cube has its side-length equal to 5cm, then its area is? For Answers

4. Find the height of a cylinder whose radius is 7 cm and the


total surface area is 968 cm2.
5. Find the height of a cuboid whose volume is 275 cm3 and
base area is 25 cm2.
6. A rectangular piece of paper 11 cm × 4 cm is folded
without overlapping to make a cylinder of height 4 cm.
Find the volume of the cylinder.
OR
Go to the link below for answers

https://cutt.ly/mensurationanswers

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