We see a radius of circle A labeled 3, so we know that the other radius of circle A that contains the side of the rectangle also measures 3 units. The side of the rectangle measures 2, so the part of the radius of circle A that is not part of the rectangle measures 1 unit. That is one leg of the right triangle.
Opposite sides of a rectangle are congruent, so the side of the rectangle opposite the side that measures 7 also measures 7. That is the other leg of the right triangle. Now we use the Pythagorean theorem to find AC which is the hypotenuse of the right triangle.
The mean = 2,000 s = Sigma ( standard deviation ) = 300 M - 2 s = 2,000- 2 * 300 = 2,000 - 600 = 1,400 M + 2 s = 2,000 + 2 * 300 = 2,000 + 600 = 2,600 Answer. Useful life of light bulbs within 2 standard deviations of the mean is: A ) Between 1,400 and 2,600 hours
