Notes on 13-3

1. JIM SMITH JCHS
SPI 3108.5.1

2. THE PROBABILITY THAT
SOMETHING WILL HAPPEN IS
THE NUMBER OF SUCCESSFUL
OUTCOMES OVER THE TOTAL
NUMBER OF OUTCOMES.

3. LET’S LOOK AT A DIE. IF YOU ROLL ONE DIE,
THERE IS ONLY 1 WAY TO
GET A 3 SO 1 WILL BE THE
NUMBER OF SUCCESSFUL OUTCOMES.
YOU CAN ROLL ANY ONE OF 6
NUMBERS SO THERE ARE 6 POSSIBLE
OUTCOMES. 6 WILL BE THE TOTAL NUMBER
OF OUTCOMES. WITH 1 DIE THE
PROBABILITY OF ROLLING A 3 IS
1/6

4. WHAT IS THE PROBABILITY OF
ROLLING A 5?
WHAT IS THE PROBABILITY OF
ROLLING A 2?
WHAT IS THE PROBABILITY OF
ROLLING A 7?

5. LET’S USE 2 DICE. NOW OUR
NUMBERS CHANGE. THE TOTAL
NUMBER OF POSSIBLE OUTCOMES
INCREASES. FOR EVERY NUMBER
WE CAN ROLL ON ONE DIE,
WE CAN ROLL ONE OF SIX NUMBERS
ON THE SECOND DIE.

6. HERE IS A TABLE
DIE 1 DIE 2
1 1,2,3,4,5,6
2 1,2,3,4,5,6
3 1,2,3,4,5,6
4 1,2,3,4,5,6
5 1,2,3,4,5,6
6 1,2,3,4,5,6
36 possibilities

7. HOW MANY WAYS CAN YOU
ROLL A 5?
Die 1 Die 2
1 4
2 3
3 2
4 1
4 SUCCESSFUL OUTCOMES

8. WHAT IS THE PROBABILITY OF
ROLLING A 5 WITH 2 DICE?
4/36 or 1/9

9. PROBABILITY THAT INVOLVES
A GEOMETRIC MEASUREMENT
SUCH AS LENGTH OR
AREA IS CALLED

10. LET’S LOOK AT GAME BOARDS
THE PROBABILITY
THAT A DART WILL
HIT A CERTAIN
COLOR IS….
THE AREA OF THAT
COLOR OVER THE
AREA OF THE
WHOLE BOARD.

11. IF THE BOARD IS DIVIDED INTO 4 EQUAL
PARTS THEN….
THE PROBABILITY OF
HITTING GREEN IS
1/4
THE PROBABILITY OF
HITTING BLUE IS
2/4 = 1/2
THE PROBABILITY OF
HITTING BLACK IS
1/4

12. FIND
THE PROBABILITY OF
A DART LANDING IN
THE DARK BLUE
10/25 = 2/5
THE LIGHT BLUE 7/25
THE BROWN 3/25
THE GREEN 5/25 = 1/5

13. 6
6
FIND
THE PROBABILITY OF
A DART LANDING IN
THE BLACK AREA

14. 6
6
AREA OF SQUARE – AREA OF CIRCLE
OVER
AREA OF SQUARE

15. 6
6
AREA OF SQUARE – AREA OF CIRCLE
OVER
AREA OF SQUARE
36 - 9π
36
(6X6) – (π3²)
(6X6)
3
4
4
1
= 4 – π
4

16. 60°
FIND THE PROBABILITY
OF A SPINNER STOPING
ON….
GREEN 90/360 = 1/4
.25 = 25%
BLUE 60/360 = 1/6
.17 = 17%
YELLOW 210/360 = 7/12
.583 = 58.3%