Created by Mr. Lafferty Maths Dept. The Circle Area of a circle Fractional area of a circle www.mathsrevision.com Exam Type Questions 21-May-19 Created by Mr. Lafferty Maths Dept.

Created by Mr. Lafferty Maths Dept. Starter Questions 6 5 www.mathsrevision.com 21-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, 21 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, 21 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, 21 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 21-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 21-May-19 Created by Mr. Lafferty Maths Dept.

Circle Now Try TJ N5 Lifeskills Ex 17.1 Ch17 (page 155) www.mathsrevision.com

Created by Mr. Lafferty Maths Dept. Starter Questions 4 www.mathsrevision.com 21-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 21-May-19 Created by Mr. Lafferty Maths Dept.

Fractional Area A = ½Πr² A = ½Π(10)² A = 157cm² Find the area for the semi-circle shape ? Solution A = ½Πr² www.mathsrevision.com 180o A = ½Π(10)² A = 157cm² Tuesday, 21 May 2019 Created by Mr Lafferty

Fractional Area A = ¼Πr² A = ¼Π(8)² A = 50.27cm² Q. Find the area of the shape below ? Solution 8cm A = ¼Πr² 90o www.mathsrevision.com A = ¼Π(8)² A = 50.27cm² Tuesday, 21 May 2019 Created by Mr Lafferty

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 21-May-19 Created by Mr. Lafferty Maths Dept.

Created by Mr. Lafferty Maths Dept. Composite Area Example : Find the area of the red part. Area = Big Circle – Small Circle 4cm www.mathsrevision.com 10cm 21-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 21-May-19 Created by Mr. Lafferty Maths Dept.

Have you updated your Learning Log ? Circle Now Try TJ N5 Lifeskills Ex 17.2 Ch17 (page 157) www.mathsrevision.com Are you on Target ? I can ?

3 marks