Answer:
A) It can shoot 15 feet long and has a rotation of 90 degrees.
We can write this area:
Area = Angle*radius^2
The radius is 15 ft.
The angle must be written in radians, so we need to writhe 90° in radians.
180° is equal to pi.
Then 90° = (90°/180°)*pi = pi/2
where pi = 3.14
Then our area is:
A = (3.14/2)*(15ft)^2 = 353.25 ft^2
B) If we have 12 of those in one yard, we can cover 12 times that area; this is:
A = 12*(353.25 ft^2) = 4239 ft^2
C) Now we want to find the angle such that the covered area for one sprinkler is equal to 1200 ft^2
Then we can replace it in the equation for the area and get:
1200ft^2 = angle*(15ft)^2 = angle*225 ft^2
angle = 1200/225 = 5.33
But this is in radians, so we may convert it to degrees.
We know that 3.14 = 180°
Then we have
5.33 rads = (5.33/3.14)*180° = 305.5°
