The Olympic Rings

1
The Olympic Rings
2
History

• The rings were adopted in 1913.
• The five rings represent the five major regions
  of the world Africa, the Americas, Asia, Europe,
  and Oceania.
• Every national flag in the world includes at
  least one of the five colors, which are blue,
  yellow, black, green, and red. 

3
Diameter and Radius

• The distance across a circle through its centre
  is called its diameter, D.
• The radius, R of a circle is the distance from
  the centre of a circle to a point on the edge of
  the circle.
• So a circle's diameter is twice as long as its
  radius D 2 R.

4
Circumference and Area

• The distance around a circle is its
  circumference, C 2 p R.
• The area, A, of a circle is
• A p R R or A p R2
• Pi, p, is the ratio of the circumference of a
  circle to its diameter.
• p 22/7
• p 3.1415926535...

C i r c u m f e r e n c e
5
Questions (use p 3.14)

• 1. The diameter of the womens discus is 21 cm.
  What is its area?
• 2. The area of a weight is 2000 cm2. What is its
  radius?
• 3. The radius of a mens discus is 11 cm. What is
  its area?
• 4. The diameter of a bicycle wheel is 0.75 m.
• What is the area of the wheel?

6
Questions
Use the ring dimensions below to answer the
questions. Remember there are 5 rings in total.

• Find the total circumference of the outer parts
  of the Olympic rings.
• Find the total circumference of the inner parts
  of the Olympic rings.
• Find the total area of the Olympic rings.

7
Answer to Question 1

• Find the total circumference of the
• outer parts of the Olympic rings
• Circumference C 2 p R
• Diameter D 2 R
• Circumference of one outer ring
• C1 2 p (D/2) p D
• C1 3.14 cm 345.4cm
• Circumference of five outer rings
• C5 5 C1 5 345.4cm 1727cm

8
Answer to Question 2
Diameter of the inner ring D 110 cm 20 cm
90 cm

• Find the total circumference of the
• inner parts of the Olympic rings
• Circumference C 2 p R
• Diameter D 2 R
• Circumference of one inner ring
• C1 2 p (D/2) p D
• C1 3.14 90 cm 282.6 cm
• Circumference of five inner rings
• C5 5 C1 5 282.6 cm 1413 cm

9
Answer to Question 3

• Find the total area of the Olympic rings
• Area of one inner circle
• A(I)1 p R(I)12 3.14 (45cm)2 6358.5cm2
• Area of one outer circle
• A(o)1 p R(o)12 3.14 (55cm)2 9498.5cm2
• Area of one ring
• A1 A(o)-A(I)1 9498.5cm6358.5cm 3140cm2
• Area of the five rings
• A5 5 A1 5 3140cm2 15700cm2

Radius of the inner ring, R(I)1 45cm Radius of
the outer ring, R(o)1 55cm
10
Bicycle Questions

• Q1. The rim of a bicycle wheel has a radius of
• 33 cm. What is the circumference of the rim of
• the wheel (to one decimal place)?
• Q2. The rim of a bicycle wheel has a diameter
• of 64cm. When the tire is mounted on the
• wheel, the diameter of the wheel increases as
• shown on the right. How much does the
  circumference of the bicycle wheel increase after
  the tire is mounted (to one decimal place)?

11
Bicycle Questions

• Q3. The wheel of Billys bike has a circumference
  of 2 m.
• How many meters will the bicycle travel when
• the wheel has made 400 revolutions?
• Q4. A bicycle wheel has a diameter of 75 cm.
• How many revolutions will the wheel make
• when it has rolled 1 km?
• Q5. A racers bicycle wheel has a diameter of 80
  cm and makes 360 revolutions per minute.
• How far will the bicycle travel in 5 minutes?

12
Homework Drawing the Olympic rings

• The rings are 11 blocks wide and 1 block thick
• (graph paper needs to be at least 37 blocks).
• Count at least 7 blocks down and draw a
  horizontal line on the graph paper (the
  centerline for the three upper rings).
• On the center line, count around 8 blocks. Mark a
  small cross (the center of ring 1).
• From Ring 1 count 12 blocks and mark a small
  cross for Ring 2.
• From Ring 2 count 12 blocks and mark a small
  cross for Ring 3.
• To locate the center for Ring 4 start at the
  center of Ring 1, count over 6 blocks, then down
  5.5 blocks. Mark a cross at this point.

13
Homework Drawing the Olympic rings

• To locate the center for Ring 5 start at the
  center of Ring 2, count over 6 blocks, then down
  5.5 blocks. Mark a cross here.
• Set the compass to a radius of 5.5 blocks
  (diameter of 11 blocks). Draw the five large
  outer circles at each of the center points.
• 8. Set the compass to a radius of 4.5 blocks
  (diameter of 9 blocks). Draw the five small inner
  circles at each of the center points.
• Erase small sections of the circles to create the
  illusion of a chain.
• Darken the object lines and color the rings
  according to the diagram.