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Gyaan Maths
CBSE · Class 6-12
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Class 6 · Ganita Prakash
Unit 6 · Class 6Ganita Prakash
Perimeter and Area
Measure the boundary and surface of 2D shapes.
Lessons
4 concepts
1
Perimeter Basics
Sum all outer side lengths. Circle circumference:
C
=
2
π
r
C = 2\pi r
C
=
2
π
r
.
2
Area of Rectangles & Squares
A
rect
=
l
×
b
A_\text{rect} = l \times b
A
rect
=
l
×
b
. Square special case:
l
=
b
=
s
l=b=s
l
=
b
=
s
, so
A
=
s
2
A=s^2
A
=
s
2
. Units: cm × cm = cm².
3
Area of Triangles
A
=
1
2
⋅
b
a
s
e
⋅
h
e
i
g
h
t
A = \tfrac 12 \cdot base \cdot height
A
=
2
1
⋅
ba
se
⋅
h
e
i
g
h
t
. Height must be perpendicular to chosen base.
4
Composite Shapes
Break into rectangles and triangles; add or subtract areas.
Skills to practise
Skill · medium
Perimeter and Area — Practice