Question 112342
IF YOU ARE SAYING THAT THERE IS A 3 IN. HOLE IN THE CENTER OF THE PLATE THEN:
AREA=PI*R^2
AREA=3.14*10^2
AREA=3.14*100
AREA=314 IN^2
THE AREA OF THE 3 IN. HOLE:
AREA=PI*3^3
AREA=3.14*9
AREA=28.26 IN^2
SUBTRACTING FOR THE AREA OF THE HOLE WE HAVE LEFT:
314-28.26=285.74 IN^2 IS THE AREA OF THE 10 IN. PLATE WITH A 3 IN. HOLE. 
285.74*7.50=$2,143.05 IS THE COST TO CONSTRUCT THIS PLATE.