The document discusses formulas for calculating the area of a sector of a circle. It states that the area of a sector is proportional to the central angle subtended, and provides the formula to calculate sector area given the radius and central angle. Examples are given of finding the radius given the sector area and central angle, and calculating the area of a specific sector using the given radius and a diagram. Formulas for finding the area of a full circle and the circumference are also stated.

1. Group 5

2. The Formula for the area of sector
 The Length of an arc is proportional to the angle
subtended at the centre of the circle
 Similarly, the area of a sector is also proportional to
the angle subtended at the centre of the circle
 The area of a sector of a circle can be calculate by
using this formulae

3. Find The Area Of a Sector given the
radius and angle at the centre
Formulae
A
Solution
O B
7 cm

4. Find The Angle Of The Centre.
Given the radius and area of sector

O
A
B

5. Find The Radius. Given The Area Of A
Sector And The Angle Of The Centre
O
B
A

6. Solve The Problem
Find The Area Of Sector
B
A
In the diagram, O is the centre
of the circle. Find the area
of Major Sector AOB. O
Answer

7. Find The Area Of Circle
In the diagram, O is the centre
of the circle. Find the Area Of Circle.
With the radius 28cm
O 14cm
Answer

8. Circles Formula
Area Of Circle Area Of Sector Circle
Circumference of Circle Length Of Arc