Geometry -need help
posted by JOY on .
A cylinder flower pot with open top needs to be painted. The height is 9 inches and radius is 3 inches. If it takes Troy 5 minutes to paint 40 square inches, how long to the minute will it take him to paint the outside of the flower pot.
I came up with 141.3 total sq inches
answer should be 25 minutes but I don't get that??
recall that the surface area of cylinder is given by
SA = 2πr^2 + 2πrh
r = radius
h = height
π = "pi" equal to 3.14 (constant)
SA = 2*(3.14)*3^2 + 2*(3.14)*3*9
SA = 226.08 in^2
then we divide this by his speed, 40 in^2/5 min:
226.08 / 8 = 28.26 minutes
hope this helps~ :)
and multiply this by 5
A wood board, 75 inches long, was cut on three pieces.
Every next piece is 5 inches longer tham the previous.
How long is the first piece?
Assign x for the length of the first piece,
create an equation and find x.