Question 732598
CIRCLE PROBLEM:
How much water can hold a kiddie pool with a 6 foot diameter when filled 1 foot high?
The surface area of the circular base, in square feet can be calculated by the formula
{{{area=pi*r^2}}} with {{{r=3}}}= radius, measured in feet (half the diameter)
{{{area=3.14*3^2=3.14*9=28.3}}} square feet (rounding {{{pi}}} and the result).
So we can fill the pool to 1 foot high with 28.3 cubic feet of water.
 
TRAPEZOID PROBLEM:
A lot has a 40 foot front on one street, with perpendicular sides measuring 70 and 50 feet, and backing to another street. What is the surface area of the lot in square feet?
{{{drawing(200,300,-10,50,-10,80,
line(-10,70,60,70),line(-20,-10,60,30),
line(0,0,0,70),line(40,20,40,70),
rectangle(0,70,2,68),rectangle(40,68,42,70),
locate(15,75,front),locate(18,69,40ft),
locate(1,35,70ft),locate(41,45,50ft)
)}}}
{{{area=(base[1]+base[2])*height/2}}} {{{area=(70ft+50ft)*40/2=2400ft^2}}}