MNU 3-11a MTH 3-11a The Circle Diameter = Circumference ÷ π Investigation of the Circle Composite shapes Perimeter

MNU 3-11a MTH 3-11a Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Created by Mr Lafferty2 Parts of the Circle Circumference O O = centre of circle The radius is measured from the centre of the circle to the edge. radius diameter The diameter is measured from one edge to the other passing through the centre of the circle.

MNU 3-11a MTH 3-11a Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Created by Mr Lafferty3 Circle Investigation Construct a table shown below to enable us to record our results.

MNU 3-11a MTH 3-11a Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Created by Mr Lafferty4 Investigation of the Circle To find a relationship between the diameter and circumference of a given circle. How can we measure the diameter and circumference O Our Investigation Question ?

MNU 3-11a MTH 3-11a Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Created by Mr Lafferty5 Measuring the Diameter of a circle The diameter is the largest distance between one side of a circle to the other passing through the centre O. O O Use a ruler

MNU 3-11a MTH 3-11a Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Created by Mr Lafferty6 Measuring the Circumference of a circle Flexible tape measure Take a tape measure and put it round the circle Read off the measurement O

MNU 3-11a MTH 3-11a Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Created by Mr Lafferty7 Measuring the Circumference of a circle Roll along an even surface One complete rotation equals the length of the circumference Be careful to avoid slip! Starting point End point

MNU 3-11a MTH 3-11a Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Created by Mr Lafferty8 Circle Investigation

MNU 3-11a MTH 3-11a Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Created by Mr Lafferty9 Circle Investigation Using your results write down, in your own words, an approximate relationship between the circumference and diameter for a given circle. “Circumference approximately equals three and bit diameters” Actual value is 3.14 which we write as π Pronounced “Pi”

MNU 3-11a MTH 3-11a 5-Jan-16Created by Mr. Lafferty Maths Dept. Now try TJ3a Ex 1 Q2 Ch10 (page 88) The Circle

MNU 3-11a MTH 3-11a 5-Jan-16Created by Mr. Lafferty Maths Dept. Starter Questions Starter Questions 4

MNU 3-11a MTH 3-11a 5-Jan-16Created by Mr. Lafferty Maths Dept. Learning Intention Success Criteria 1.Recall knowledge of circles so far. 1. We are learning to calculate the perimeter of composite shapes that including parts of a circle. Perimeter 2.Solve mixed problems by applying all our knowledge so far.

MNU 3-11a MTH 3-11a 5-Jan-16Created by Mr. Lafferty Maths Dept. Main Parts of a Circle Main parts of the circle radius O Circumference Diameter

MNU 3-11a MTH 3-11a 5-Jan-16Created by Mr. Lafferty Maths Dept. Calculating the Circumference 10cm 2cm Example : Find the length of the circumference (Perimeter) of each circle

MNU 3-11a MTH 3-11a Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Created by Mr Lafferty15 Example Calculate the curved part of this shape. Solution 6m 90 o Calculating the Circumference

MNU 3-11a MTH 3-11a Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Created by Mr Lafferty16 Example Find the perimeter for the semi-circle shape ? Solution 180 o Composite Perimeter

MNU 3-11a MTH 3-11a Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Tuesday, 05 January 2016Created by Mr Lafferty17 Example Find the perimeter of the shape below ? Solution 8cm 90 o Composite Perimeter

MNU 3-11a MTH 3-11a 5-Jan-16Created by Mr. Lafferty Maths Dept. Example : Find the perimeter of this shape 20cm 5 cm Perimeter = 3 sides + semicircle Composite Perimeter

MNU 3-11a MTH 3-11a 5-Jan-16Created by Mr. Lafferty Maths Dept. Now try TJ3a Ex 2 Ch10 (page 91) The Circle

MNU 3-11a MTH 3-11a 5-Jan-16Created by Mr. Lafferty Maths Dept. Starter Questions Starter Questions

MNU 3-11a MTH 3-11a 5-Jan-16Created by Mr. Lafferty Maths Dept. Learning Intention Success Criteria 1. We are learning to find the diameter of a circle if we know the circumference. Finding the Diameter The Circle 2.Solve diameter problems. 1.Understand how to rearrange circumference formula to find diameter.

MNU 3-11a MTH 3-11a 5-Jan-16Created by Mr. Lafferty Maths Dept. We can easily rearrange the circumference formula so that we have the diameter D on one side. Finding the Diameter The Circle You have 1 minute to rearrange equation. Remember change side change sign

MNU 3-11a MTH 3-11a 5-Jan-16Created by Mr. Lafferty Maths Dept. C = 62.8 cm Examples : Find the diameter of each circle given the circumference. 2 0 c m C =15.7 cm 5 c m Finding the Diameter The Circle

MNU 3-11a MTH 3-11a 5-Jan-16Created by Mr. Lafferty Maths Dept. Now try TJ3a Ex 3 Ch10 (page 93) The Circle Have you updated your Learning Log ?