This document discusses the formulas for calculating the circumference and area of circles. It defines circumference as π x diameter and area as π x radius squared. It provides examples of using these formulas to find the circumference and area of various circles. Finally, it poses two questions asking the reader to apply the formulas to calculate the circumference and area of two additional circles.

1. Geometry
Area and Circumference of a Circle

2. Circumference
circumference
Circumference =
diameter
π × diameter

3. Area
Area
radius = π × radius × radius
= π × radius2
area

4. C ircumference is
π x diameter
π x diameter
π x diameter
Circumference is
π x diameter
Area is πr2

5. Example 1
Find the circumference of this circle
circumference
Circumference
= π × diameter
4cm Circumference
=π×4
= 12·57cm (2 d.p.)

6. Example 2
Find the circumference of this circle
circumference
Circumference
= π × diameter
8cm Circumference
= π × 16
= 50·27cm (2 d.p.)

7. Example 1
Find the area of this circle
Area
= π × radius × radius
7cm
Area
= π×7×7
area
= 153·94cm² (2 d.p.)

8. Example 2
Find the area of this circle
Area
= π × radius × radius
10cm
Area
area = π×5×5
= 78·54cm² (2 d.p.)

9. Question 1
Find the circumference and area of this circle
Circumference = π × diameter
Circumference = π × 9
= 28·27cm (2 d.p.)
9cm
Area = π × radius × radius
Area = π × 4·5 × 4·5
= 63·62cm² (2 d.p.)

10. Question 2
Find the circumference and area of this circle
Circumference = π × diameter
Circumference = π × 12
= 37·70cm (2 d.p.)
6 cm
Area = π × radius × radius
Area = π × 4·5 × 4·5
= 113·10cm² (2 d.p.)