Jamie bought a floor planter shaped like a horse trough (half a cylinder). if the length is 30 inches and the diameter is 12.5 inches, how much dirt does jamie need to buy to fill the planter?

The volume of half a cylinder is given by:
 V = (1/2) * (pi) * (r ^ 2) * (L)
 Where,
 r : cylinder radius
 L: cylinder length.
 Substituting values we have:
 V = (1/2) * (3.14) * ((12.5 / 2) ^ 2) * (30)
 V = 1839.84375
 Rounding off we have:
 V = 1840 in ^ 3
 
 jamie needs to buy 1840 in ^ 3 of dirt to fill the planter

We know that
volume of half cylinder=pi*r²*h/2
diameter=12.5 in
r=12.5/2> 6.25 in
h=30 in

volume of half cylinder=pi*6.25²*30/2> 1839.84 in³

the answer is
1839.84 in³