Mariah borrowed 15 books from the library last month. She's already read of them. How many of the 15 books has she read?

Most probably 7. Since you can't read half a book and say you completed it. I don't think you wrote the question right though.

d 25 pi/6

step-by-step explanation:

the diameter is 10 inches

the radius is 1/2 of the diameter or 5 inches

the area of the circle is

a = pi r^2

  = pi 5^2

  = 25 pi

the slice is 60 degrees of the entire circle.

60 degrees out of 360   60/360 = 1/6

the area of the slice is 1/6 of the circle

a slice = 1/6 a circle

a slice = 1/6 * 25 pi