Area of a Circle π. Starter Which of these shapes has the greatest perimeter? Which has the smallest? What is each perimeter in terms of d? d d d.

Slides:

Advertisements

Similar presentations

Areas of Circles and Sectors

Advertisements

Area & Perimeter Area of a rectangle = Area of a triangle = Area of a parallelogram = Area of a trapezium =

AREA AND CIRCUMFERENCE OF A CIRCLE. diameter radius circumference The perimeter of a circle is called the circumference (C). The diameter (d) of a circle.

Definition: A circle is the set of all points on a plane that is a fixed distance from the center.

Level 3 14-Aug-15Created by Mr. Lafferty Maths Dept. The Circle Circumference of the circle Diameter = Circumference ÷ π Area of.

Circles: Area and Circumference. Definitions Circumference: Distance around the outside of a circle Area: How many squares it takes to cover a circle.

The distance around the outside of a shape.

Area - Revision The area of a shape is simply defined by : “the amount of space a shape takes up.” Think of a square measuring 1 cm by 1cm we say it is.

1)Create a circle with a diameter of 6 cm. 2) Using a ruler, divide the circle into 8 congruent sectors. 3)Cut out the sectors and arrange them to form.

Area and Perimeter.

Measurement Jeopardy CirclesPerimeter Area 3-D Surface Area And Volume $100 $200 $300 $400 $500 $100 $200 $300 $400 $500.

$100 Area of Parallelograms Area of Triangles Perimeter And Area Area of Trapezoids Area of Compound Figures & Area and Circumference of Circles $200.

© 2008 Pearson Addison-Wesley. All rights reserved Chapter 1 Section 9-3 Perimeter, Area, and Circumference.

Areas of Polygons and Circles

Circles/Triangles Sector Area/ Arc Length Formulas Special Quads Polygons

Perimeter & Area Area of Shapes The area of a shape is the space it occupies. Try guessing the name of these shapes first: Square Rectangle ParallelogramTrapezium.

5.1, 5.2, 5.3 Area, Perimeter, Circumference. Parallelograms Area & perimeter A = bh P = 2 l + 2 w Area & perimeter A = ½ bh P = add the exterior sides.

Section 9-4 Perimeter, Area, and Circumference.

What is the area of a circle?

= (2 in) · (2 in) = 4 in 2. P = a + b + c A = ½(8*8) A = 32 P = =20.

Facts about Area of Shapes Dr. Kent Bryant 5/2011.

Geometry 7 th Grade Math Ms. Casazza Click on the button to go the next slide!

Chapter 11 Areas of Polygons and Circles Areas of Parallelograms  The height is always perpendicular to the base h b w l A = bh A =lw A = s 2 s.

Rectangle l - length w - width Square s – side length s s s.

Objective: To be able to use the formula for the Curved Surface Area of a Cone, alongside other mathematical topics.

Perimeter, Circumference, and Area Learning Target: I can find the perimeter, circumference, and area of basic shapes.

The circumference of the circle is 50  feet. The area of the shaded region = ________ example 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.

Starter The perimeter of this sector is (2r + 12∏) m. Find the radius r m, of the sector. r m.

Practice with Area, Perimeter and Circumference Sometimes we have to find area or perimeter of odd shapes. Find the area of the following shape. 15 m.

1 of 84 SHAPE AND SPACE Circles. 2 of 84 The circumference of a circle Use π = 3.14 to find the circumference of this circle. C = πd 8 cm = 3.14 × 8 =

Area & Perimeter. SHAPE OVERVIEW Rectangle Triangle Hexagon Trapezoid Square Parallelogram Pentagon Circle.

The Circle. The language of circles Circumference: The distance round the circle Circumference: The distance round the circle Diameter: the distance from.

Circumference Lesson #33. What is Circumference? The distance around the outside of a circle is called the circumference (essentially, it is the perimeter.

Revision Formulae: Diameter = 2 x Radius Area of Circle = πr 2 Circumference of circle = 2πr = πd π = 3.14 approximately.

1.7 - Find Perimeter, Circumference, and Area. Perimeter: Length around a shape. Measured in u cm, in, ft, yd.

Chapter 12 Lateral and Surface Areas Lateral and Surface Areas of Prisms h L = Ph SA = L + 2B P = Perimeter of the base (bottom) h *base (shape.

Area and Perimeter.

Circles, Polygons, Circumference and Perimeter WHAT CAN YOU DEDUCE, GIVEN VERY LITTLE INFORMATION?

Perimeter and Area A look at a few basic shapes Perimeter.

Area, Circumference & Perimeter

Lesson 1-7: Perimeter,Circumference & Area Warmup A has coordinates (3, 8). B has coordinates (0, –4). C has coordinates (–5, –6). 1. Find the distance.

Circles…… Area and Circumference The Circumference of a Circle Find the circumference of the following circles. C =  d C = 2  r 8 cm cm 2 C =

Circles Shape and Space. Formula for the area of a circle We can find the area of a circle using the formula radius Area of a circle = πr 2 Area of a.

Finding Perimeter and Area Review. Perimeter The distance around the outside of an object. 10 feet 8 feet 10 feet Perimeter = = 36 feet.

CIRCLES CIRCUMFERENCE & AREA. CIRCUMFERENCE C = ΠdorC = 2Πr 12cm.

Starter Find the Perimeter and Area of this shape… 12m 15m Perimeter 15m + 15m + 12m = 42m C = πd C = π x 12 C = 37.70m (2dp) Semi circle so… ÷

Perimeter, Circumference and Area. Perimeter and Circumference Perimeter : The distance around a geometric figure. Circumference: The distance around.

Half the circumference

Area & Perimeter. Page ________ of Notebook Title: Area and Perimeter Title: Area and Perimeter Objective: Find Area and Perimeter Objective: Find Area.

Objective: To identify regular polygons. To find area, perimeter and circumference of basic shapes. Perimeter, Circumference, Area Name Class/Period Date.

Perimeter The distance around the outside of a shape.

Perimeter and Area with Circles. Circumference of a Circle Circumference is the perimeter of the circle Formula: or (for exact answers, leave π in your.

Sections Perimeter and Area with Circles.

Welcome to RSP Math Mrs.Muljodiredjo.

Solve Problems Involving the Circumference and Area of Circles

Area of Shapes.

UNIT 8: 2-D MEASUREMENTS PERIMETER AREA SQUARE RECTANGLE PARALLELOGRAM

STARTERS Find the area of Trapezium = 750 Rectangle = 1000

Choose a shape and write down everything you know about it.

Area and Perimeter Ten quick questions.

Area & Perimeter.

1.7 Introduction to Perimeter, Circumference, & Area

Area of Parallelograms and Triangles

Area of Plane Shapes.

Starter Which of these shapes has the greatest perimeter?

Presentation transcript:

Area of a Circle π

Starter Which of these shapes has the greatest perimeter? Which has the smallest? What is each perimeter in terms of d? d d d

Starter Answer Square has 4 sides of length d 4d Hexagon has 6 sides of ½d3d d d d ½d

Starter Answer Square has 4 sides of length d 4d Hexagon has 6 sides of ½d3d Circle is between 3d and 4dπd

Areas Which of these shapes has the greatest area? Which has the smallest? What is the area in terms of r? rrr

Areas Large square is 2r x 2r = 4r 2 Small square is half of this = 2r 2 rrr 2r

Areas Large square is 2r x 2r = 4r 2 Small square is half of this = 2r 2 Circle has area in between 2r 2 and 4r 2

Area of a circle A circle has radius r

Rearrange the sectors

Consider the lengths Circumference of circle = 2πr Length of half circumference = πr So the length of this side is πr

Consider the lengths Radius of circle = r So the height is r πrπr

Consider the area Area of shape is close to area of parallelogram = base x height = πr x r = πr 2 r πrπr Hence the area of a circle is = πr 2

Summary A circle has radius r and diameter d Circumference of a circle C = π d or C = 2 π r Area of a circle A = π r 2 r d Fiddle-dee-dum, fiddle-dee-dee A ring round the moon is π times d But if you want a hole repaired Then what you need is πr 2.