Three concentric circles are drawn with radii of 8 cm, 12 cm, and 20cm. If a dart lands randomly on this target, what are the probabilities of it landing in each region?
2007-08-19 10:51:08 · 1 answers · asked by cool :-D 1 in Science & Mathematics ➔ Mathematics
Calculate the ratio of the areas of the three circles.
Area = πr²
20 cm circle Area = 400π
12 cm circle Area = 144π
8 cm circle Area = 64π
Probability of hitting circle.
20 cm circle = 400π/400π = 1
Since it is given that the target is hit.
12 cm circle = 144π/400π = 0.36
8 cm circle = 64π/400π = 0.16
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If by region you mean inside the given circle but outside any smaller circle the probabilities are:
8 cm circle = 64π/400π = 0.16
12 cm circle = (144π - 64π)/400π = 0.20
20 cm circle = (400π - 144π)/400π = 0.64
2007-08-19 11:00:07 · answer #1 · answered by Northstar 7 · 0⤊ 0⤋