2. GEOMETRY • Circumference of a circle
• The perimeter of a circle is called
it’s circumference .
• The circumference , diameter,and
radius are denoted as c ,d and r
respectively.
• The ratio of circumference and
radius is a constant.
MENSURATION
3. AREA
• Area of a circle=πr2
•Area of a circular annulus=
Area of a circle
Area of a circular annulus
Area of a sectorial region