7th Maths : Term 2 Unit 2 : Measurements : Summary

**Summary**

● Circle is a round plane figure whose
boundary (the circumference) consists of points equidistant from the
fixed point ( the centre).

● Distance around the circular region
is called the circumference or perimeter of the circle.

● Circumference of a circle, *C* = π*d* *units*, where ‘*d*’ is the diameter of
a circle and π* *=*
*22/7* *or
3.14 approximately.

● Area of the circle is the region enclosed
by the circle.

● The area of the circle, (A) = π *r*^{2} *sq.
units*, where ‘*r*’ is
the radius of the circle.

● Area of the circular path = Area of
the outer circle – Area of the inner circle

= π *R*^{2} − π *r*^{2} = π (*R*^{2} − *r*^{2} ) *sq. units*, where ‘*R*’ and ‘*r*’ are
radius of
the outer and inner circles respectively.

● Area of the rectangular path = Area
of the outer rectangle – Area of the inner rectangle

=
(*LB* −
*lb*) *sq.units*, where *L, B*, and *l, b* are length and breadth
of outer and inner rectangles respectively.

__ICT Corner__

**Expected Result is shown in this picture**

**Step-1 :**

Open the Browser type the URL Link given
below (or) Scan the QR Code. GeoGebra work sheet named “Mensuration” will open.
There are two activities named “Area by Activity” and “Circular path problem”

**Step-2 :**

In the first activity move the slider
n (No. of divisions) and the slider *r* (to increase the radius). As the no.
of division increases it becomes almost a rectangle with Length = half the circumference
and breadth equal to the radius. Thus the area = Length × Breadth = πr^{2}. Also try
the second activity.

Browse in
the link

Measurements:
https://www.geogebra.org/m/f4w7csup#material/bztgqe8q
or Scan the QR Code.

Tags : Measurements | Term 2 Chapter 2 | 7th Maths , 7th Maths : Term 2 Unit 2 : Measurements

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7th Maths : Term 2 Unit 2 : Measurements : Summary | Measurements | Term 2 Chapter 2 | 7th Maths

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