1. Note 2: Perimeter The perimeter is the distance around the outside of a shape. Start at one corner and work around the shape calculating any missing sides. 6 cm 5 cm 2 cm 5 cm Perimeter = 5cm + 3cm + 6cm + 2cm + 11cm + 5cm = 32cm

2. Note 3: Circumference The perimeter of a circle is called the circumference. The formula for the circumference is: C = πd or C = 2πr where d = diameter r = radius. Example: Find the circumference of C = 2πr = 2 x π x 8cm = 50.3cm (1dp)

3. If a sector has an angle at the centre equal to x, then the arc length is x / 360 of the circumference. Example: Find the perimeter of the sector Angle of sector = 360 ° - 120 ° = 240 ° Arc Length = x / 360 x 2πr = 240 / 360 x 2 x π x 6m = 25.1m (1dp) Perimeter = 2 x 6m + 25.1m = 37.1m

4. Page 334 Exercise 11B