Question

A circle with a radius of 10 inches is placed inside a square with a side length of 20 inches. Find the probability that a dart thrown will land inside the circle.

a. 87.5%
b. 75.8%
c. 57.8%
d. 78.5&

Answer 1

I think the answer is 78.5 . I mean it should be , if you don’t get it right I’m sorry !

Answer 2

The correct answer is last option 78.5%

Explanation:

Points to remember

Area of circle = πr²

Where r is the radius of circle

Area of square = a²

Where 'a' is the side length of square

To find the area of circle

Here r = 10 cinches

Area = πr²

= 3.14 * 10²

= 3.14 * 100 = 314

To find the area of square

Here a = 20 inches

Area = a²

= 20²

= 400

To find the probability percentage

Probability = area of circle/Area of square

= (314/400)*100

78.5 %