7-8 Geometric Probability

L.E.Q. How do you use segment and area models to find the probabilities of events?

You may recall that the probability of an event is the ratio of the number of favorable outcomes to the number of possible outcomes.

Remember Probability:

Geometric Probability:

A gnat lands at a random point on the ruler’s edge. Find the probability that the point is between 3 and 7.

Finding Probability Using Segments.

Elena’s bus runs every 25 minutes. If she arrives at her bus stop at a random time, what is the probability that she will have to wait at least 10 minutes for the bus?

Real-World Connection

Assume that a dart you throw will land on the 1-ft square dartboard and is equally likely to land at any point on the board. Find the probability of hitting each of the blue, yellow, and red regions. The radii of the concentric circles are 1, 2, and 3 inches, respectively.

Finding Probability Using Area.

To win a prize in a carnival game, you must toss a quarter so that it lands entirely within the circle as shown below. Find the probability of this happening on one toss. Assume that the center of a tossed quarter is equally likely to land at any point within the 8-in. square.

Real-World Connection

Pgs. 404-406 #s 2-20 even, 23-25 all.

Homework: