Circumference 𝑪=𝝅𝒅 𝑪=𝟐𝝅𝒓

Write the formula first ! Pg 176 Exercise 9b No. 13, 15, 16, 17 Homework Write the formula first ! Pg 176 Exercise 9b No. 13, 15, 16, 17

Homework Check 13. Radius 154 mm 𝑪=𝟐𝝅𝒓 𝑪=𝟐×𝝅×𝒓 𝑪=𝟐×𝝅×𝟏𝟓𝟒 𝑪=𝟗𝟕𝟎 𝒎𝒎 (𝟐 𝒔.𝒇.)

Homework Check 15. Radius 7.7 m 𝑪=𝟐𝝅𝒓 𝑪=𝟐×𝝅×𝒓 𝑪=𝟐×𝝅×𝟕.𝟕 𝑪=𝟒𝟖 𝒎 (𝟐 𝒔.𝒇.)

Homework Check 16. Radius 34.6 cm 𝑪=𝟐𝝅𝒓 𝑪=𝟐×𝝅×𝒓 𝑪=𝟐×𝝅×𝟑𝟒.𝟔 𝑪=𝟐𝟐𝟎 𝒄𝒎 (𝟐 𝒔.𝒇.)

Homework Check 17. Diameter 511 mm 𝑪=𝝅𝒅 𝑪=𝝅×𝒅 𝑪=𝝅×𝟓𝟏𝟏 𝑪=𝟏𝟔𝟎𝟎 𝒎𝒎 (𝟐 𝒔.𝒇.)

Circumference 𝑪=𝝅𝒅 𝑪=𝟐𝝅𝒓

=𝝅𝒅 𝟑𝟕𝟔.𝟖𝟎=𝝅𝒅 𝟑𝟕𝟔.𝟖𝟎 𝝅 =𝒅 𝟏𝟏𝟗.𝟗𝟒𝒄𝒎=𝒅 Circumference FIND THE DIAMETER of a circle with a CIRCUMFERENCE OF 376.80 CM. WORKING: 376.80cm Circumference =𝝅𝒅 𝟑𝟕𝟔.𝟖𝟎=𝝅𝒅 𝟑𝟕𝟔.𝟖𝟎 𝝅 =𝒅 𝟏𝟏𝟗.𝟗𝟒𝒄𝒎=𝒅 Tuesday, November 13, 2018

Find the radius of a circle if its circumference is ……... (a) 25.12 cm Answer: 4 cm (b) 37.68 m Answer: 6 m Round your answer to the nearest whole number! Tuesday, November 13, 2018

Draw Half a Circle

Draw a Quarter Circle

𝐶𝑖𝑟𝑐𝑢𝑚𝑓𝑒𝑟𝑒𝑛𝑐𝑒 𝑜𝑓 𝑆𝑒𝑚𝑖−𝐶𝑖𝑟𝑐𝑙𝑒=25.1 ÷𝟐=12.6𝑐𝑚 Perimeter Find the perimeter of this shape 8cm 𝐶=𝜋𝑑 𝐶=𝜋×8 =25.1 𝑐𝑚 (1𝑑𝑝) 𝐶𝑖𝑟𝑐𝑢𝑚𝑓𝑒𝑟𝑒𝑛𝑐𝑒 𝑜𝑓 𝑆𝑒𝑚𝑖−𝐶𝑖𝑟𝑐𝑙𝑒=25.1 ÷𝟐=12.6𝑐𝑚 Length of diameter = 8cm Perimeter of shape = 12.6 + 8 = 20.6cm(1dp)

𝐶𝑖𝑟𝑐𝑢𝑚𝑓𝑒𝑟𝑒𝑛𝑐𝑒 𝑜𝑓 𝑄𝑢𝑎𝑟𝑡𝑒𝑟−𝐶𝑖𝑟𝑐𝑙𝑒 Perimeter Find the perimeter of this shape 3cm 𝐶=2𝜋𝑟 𝐶=2×𝜋×3 =18.8 𝑐𝑚 (1𝑑𝑝) 𝐶𝑖𝑟𝑐𝑢𝑚𝑓𝑒𝑟𝑒𝑛𝑐𝑒 𝑜𝑓 𝑄𝑢𝑎𝑟𝑡𝑒𝑟−𝐶𝑖𝑟𝑐𝑙𝑒 =18.8 ÷𝟒=4.7 𝑐𝑚 Length of radii = 3cm + 3cm = 6cm Perimeter of shape= 4.7 + 6 =10.7cm(1dp)

𝐶𝑖𝑟𝑐𝑢𝑚𝑓𝑒𝑟𝑒𝑛𝑐𝑒 𝑜𝑓 𝑆𝑒𝑚𝑖−𝐶𝑖𝑟𝑐𝑙𝑒=31.4 ÷𝟐=15.7𝑐𝑚 Perimeter Find the perimeter of this shape 𝐶=𝜋𝑑 𝐶=𝜋×10 =31.4 𝑐𝑚 (1𝑑𝑝) 3cm 𝐶𝑖𝑟𝑐𝑢𝑚𝑓𝑒𝑟𝑒𝑛𝑐𝑒 𝑜𝑓 𝑆𝑒𝑚𝑖−𝐶𝑖𝑟𝑐𝑙𝑒=31.4 ÷𝟐=15.7𝑐𝑚 10cm Length of straight sides = 3 + 3 +10 =16cm Perimeter of shape = 15.7 + 16 = 31.7cm(1dp)

Worksheet: Finding the Perimeter