Mensuration Class 6 PPT

 Page 1


Introduction
Topic dealing with the use of formulae to calculate Perimeters, 
Areas and Volumes of plain shapes and solid ones (prisms).
Plane:
A plane is a flat surface (think tabletop) that extends forever in all 
directions.
It is a two-dimensional figure.
Three non-collinear points determine a plane.
So far, all of the geometry we’ve done in these lessons took place 
in a plane.
But objects in the real world are three-dimensional, so we will 
have to leave the plane and talk about objects like spheres, boxes, 
cones, and cylinders.
Solid: Geometric figure in three dimensions
Surface Area: Total area of all the surfaces of a solid shape or 
prism.
Volume: This is the space occupied by a solid shape or prism.
Page 2


Introduction
Topic dealing with the use of formulae to calculate Perimeters, 
Areas and Volumes of plain shapes and solid ones (prisms).
Plane:
A plane is a flat surface (think tabletop) that extends forever in all 
directions.
It is a two-dimensional figure.
Three non-collinear points determine a plane.
So far, all of the geometry we’ve done in these lessons took place 
in a plane.
But objects in the real world are three-dimensional, so we will 
have to leave the plane and talk about objects like spheres, boxes, 
cones, and cylinders.
Solid: Geometric figure in three dimensions
Surface Area: Total area of all the surfaces of a solid shape or 
prism.
Volume: This is the space occupied by a solid shape or prism.
Areas of geometrical shapes
l
w
l ? w
a
a
a ? a
b
h 1/2  b ? h
h
b
b ? h
Shape Diagram Area
Page 3


Introduction
Topic dealing with the use of formulae to calculate Perimeters, 
Areas and Volumes of plain shapes and solid ones (prisms).
Plane:
A plane is a flat surface (think tabletop) that extends forever in all 
directions.
It is a two-dimensional figure.
Three non-collinear points determine a plane.
So far, all of the geometry we’ve done in these lessons took place 
in a plane.
But objects in the real world are three-dimensional, so we will 
have to leave the plane and talk about objects like spheres, boxes, 
cones, and cylinders.
Solid: Geometric figure in three dimensions
Surface Area: Total area of all the surfaces of a solid shape or 
prism.
Volume: This is the space occupied by a solid shape or prism.
Areas of geometrical shapes
l
w
l ? w
a
a
a ? a
b
h 1/2  b ? h
h
b
b ? h
Shape Diagram Area
Shape Diagram Area
? r
2
r
½(a +b)h
a
h
b
Page 4


Introduction
Topic dealing with the use of formulae to calculate Perimeters, 
Areas and Volumes of plain shapes and solid ones (prisms).
Plane:
A plane is a flat surface (think tabletop) that extends forever in all 
directions.
It is a two-dimensional figure.
Three non-collinear points determine a plane.
So far, all of the geometry we’ve done in these lessons took place 
in a plane.
But objects in the real world are three-dimensional, so we will 
have to leave the plane and talk about objects like spheres, boxes, 
cones, and cylinders.
Solid: Geometric figure in three dimensions
Surface Area: Total area of all the surfaces of a solid shape or 
prism.
Volume: This is the space occupied by a solid shape or prism.
Areas of geometrical shapes
l
w
l ? w
a
a
a ? a
b
h 1/2  b ? h
h
b
b ? h
Shape Diagram Area
Shape Diagram Area
? r
2
r
½(a +b)h
a
h
b
AREA
The  perimeter of 
a shape is a 
measure of 
distance around 
the outside.
The area of a shape 
is a measure of the
surface/space 
contained within its
perimeter.
Area is measured in units
2
Units of distance
mm
cm
m
km
inches
feet
yards
miles
1 cm
1 cm
2
1 cm
1 cm
Units of area
mm
2
cm
2
m
2
km
2
inches
2
feet
2
yards
2
miles
2
Page 5


Introduction
Topic dealing with the use of formulae to calculate Perimeters, 
Areas and Volumes of plain shapes and solid ones (prisms).
Plane:
A plane is a flat surface (think tabletop) that extends forever in all 
directions.
It is a two-dimensional figure.
Three non-collinear points determine a plane.
So far, all of the geometry we’ve done in these lessons took place 
in a plane.
But objects in the real world are three-dimensional, so we will 
have to leave the plane and talk about objects like spheres, boxes, 
cones, and cylinders.
Solid: Geometric figure in three dimensions
Surface Area: Total area of all the surfaces of a solid shape or 
prism.
Volume: This is the space occupied by a solid shape or prism.
Areas of geometrical shapes
l
w
l ? w
a
a
a ? a
b
h 1/2  b ? h
h
b
b ? h
Shape Diagram Area
Shape Diagram Area
? r
2
r
½(a +b)h
a
h
b
AREA
The  perimeter of 
a shape is a 
measure of 
distance around 
the outside.
The area of a shape 
is a measure of the
surface/space 
contained within its
perimeter.
Area is measured in units
2
Units of distance
mm
cm
m
km
inches
feet
yards
miles
1 cm
1 cm
2
1 cm
1 cm
Units of area
mm
2
cm
2
m
2
km
2
inches
2
feet
2
yards
2
miles
2
Area of a rectangle
Examples
To Find the area of a rectangle simply multiply the 2 
dimensions together. Area = l x w (or w x l)
Find the area of each rectangular shape below.
100 m
50 m
120 m
40 m
1
2
3
4
5
8½ cm
5½ cm
90 feet
50 feet
210 cm
90 cm
5 000 m
2
4500 ft
2
4 800 m
2
46.75 cm
2
18 900 cm
2