11-8 Geometric 11-8 Geometric ProbabilityProbability

ExampleExample

If you threw a magnet and it landed on the picture from the warm up, what is the probability that the magnet lands inside the small circle? (known as the “bull’s eye”)

Area you are trying for

Total Area

16

64

1

4

RULE:RULE:

To find the Geometric Prob:

Area of what they ask for

Area of WHOLE shape

ExampleExample

Draw a line GR

Draw point L as the midpoint of GR

Draw point A as the midpoint of LR

Draw point H as the midpoint of AR

What portion of GR is LH?

G RL A H

4 2 1 1

3/8

ExampleExample

• A subway stops every 20 minutes, waits 3 minutes and then leaves.

If you arrive at a random time, what is the prob. you will be able to board the train?

Shortcut: It’s always “little”/”big” –Reduce when necessary!!

3_

20

TOOTOO

• Page 462 #1-3

• ***Watch Out #1—Use RW not whole line

Answers:

1)a) 1/5 b) 3/5 c) 4/5

d) 1 e) 0 f) 1

2) 1/3

3) 15π/100 = 0.471, π/100 = 0.031

HomeworkHomework

• Page 463 #1-5,skip 4b

• Pg. 465 Self Test #1-7, skip 6b

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