The answer is ten hope this helps :-)
Area of the field should be 9*10 = 90 square feet.
a bag of grass seeds cover 15 square feet.
so if you need to know how many bags should be used, then,
Total area of field/ area covered by 1 bag of grass seeds.
= 90/15 = 6 bags
he needs to use 6 bags of grass seeds to cover the whole field.
I don't think there are any 'hidden' questions, though you can consider the 2nd part of the question I guess. (how many bags of seed will Paul...)
You can find the perimeter of a circle by using the radius.
circumference = 2

Circumference = 2

circumference = 24 pi
Since you are only trying to find half of the circle you would divide your answer by 2
24pi / 2 = 12 pi
12 pi = 37.68
The answer is B. 37.7
Answer: choice D) 20
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Explanation:
Locate 3 on the x axis number line. Draw a vertical line through 3 and this vertical line will cross the parabola at some point P. Mark this point P on the parabola. Then draw a horizontal line from P to the y axis. The horizontal line will land on y = 10. In short, this all shows us that (3,10) is a point on this parabola.
Repeat those steps above, but now for x = 7. You'll see that (7,90) is another point on this parabola.
We need to find the slope of the line through the two points (3,10) and (7,90). The average rate of change from x = 3 to x = 7 is the same as the slope of the line through those two points.
To find the slope, we use the slope formula
m = (y2 - y1)/(x2 - x1)
where (x1,y1) and (x2,y2) are the two points, and m is the slope
In this case,
(x1,y1) = (3,10) and (x2,y2) = (7,90)
further breaking down to
x1=3
y1=10
x2=7
y2=90
So we'll plug those four pieces of info into the equation and simplifying to get...
m = (y2 - y1)/(x2 - x1)
m = (90 - 10)/(7 - 3)
m = 80/4
m = 20
The slope of the line is 20, so therefore, the average rate of change is 20.
Answer: 
<u>Multiply</u>
60%×1200=720
Note: When finding the percent of a number always multiply the percent times the number.