Created by Mr. Lafferty Maths Dept. The Circle Area of a circle Fractions of a circle www.mathsrevision.com 7-May-19 Created by Mr. Lafferty Maths Dept.

Created by Mr. Lafferty Maths Dept. Starter Questions 6 5 www.mathsrevision.com 7-May-19 Created by Mr. Lafferty Maths Dept.

Area of a Circle www.mathsrevision.com Peeling an orange A circumference A B x x O O www.mathsrevision.com What do we call the distance OA in terms of the large circle. What do we call the distance AB in terms of the large circle.

Created by Mr. Lafferty Maths Dept. Area of a Circle O A x B What is the formula for the area of a right-angle triangle. Use this formula to work out the area for a circle. www.mathsrevision.com 7-May-19 Created by Mr. Lafferty Maths Dept.

And lay them out side by side Area of a Circle If we break the circle into equal sectors And lay them out side by side We get very close to a rectangle. 1 2 3 4 5 6 7 8 www.mathsrevision.com 4 5 6 7 8 2 3 1 Demo Tuesday, 07 May 2019 Created by Mr Lafferty

Area of a Circle www.mathsrevision.com 8 2 4 6 3 1 5 7 If we cut the sectors Thinner and thinner then we get closer and closer to a rectangle. Hence we can represent the area of a circle by a rectangle. 1 2 3 4 5 6 7 8 thinner and thinner sectors www.mathsrevision.com Tuesday, 07 May 2019 Created by Mr Lafferty

Area = πr2 Area of a Circle www.mathsrevision.com But the area inside this rectangle is also the area of the circle Area = πr2 Tuesday, 07 May 2019 Created by Mr Lafferty

Created by Mr. Lafferty Maths Dept. Area of a circle Q. Find the area of the circle ? Solution 4cm www.mathsrevision.com 7-May-19 Created by Mr. Lafferty Maths Dept.

Created by Mr. Lafferty Maths Dept. Area of a circle The diameter of the circle is 60cm. Find area of the circle? Solution www.mathsrevision.com 7-May-19 Created by Mr. Lafferty Maths Dept.

Created by Mr. Lafferty Maths Department Area Now try TJ3a Ex 1 Ch14 (page 126) www.mathsrevision.com 7-May-19 Created by Mr. Lafferty Maths Department

Created by Mr. Lafferty Maths Dept. Starter Questions 4 www.mathsrevision.com 7-May-19 Created by Mr. Lafferty Maths Dept.

Created by Mr. Lafferty Maths Dept. Mixed Problems The Circle Learning Intention Success Criteria 1. We are learning to solve problems by applying our knowledge of circles. Recall knowledge of circles so far. 2. Solve mixed problems by applying all our knowledge so far. www.mathsrevision.com 7-May-19 Created by Mr. Lafferty Maths Dept.

Created by Mr. Lafferty Maths Dept. Mixed Problems The Circle Example 1 : Find the area of the shape Area = rectangle + semicircle 20cm 5 cm www.mathsrevision.com 7-May-19 Created by Mr. Lafferty Maths Dept.

Created by Mr. Lafferty Maths Dept. Mixed Problems The Circle Example 2 : A circle is contained in a square. Find the grey shaded area below. 8cm Area = square - circle www.mathsrevision.com 7-May-19 Created by Mr. Lafferty Maths Dept.

Area Now try TJ3a Ex 2 Ch14 (page 128) www.mathsrevision.com Have you updated your Learning Log ? Area Now try TJ3a Ex 2 Ch14 (page 128) www.mathsrevision.com Are you on Target ? I can ? 7-May-19 Created by Mr. Lafferty Maths Department