Answer
$A: 0,0 \\ B: c,d \\ C: b,d \\ D: a,0 $
Work Step by Step
An ideally placed trapezoid, which we will call trapezoid ABC, should have point A placed at the origin and side AD be on the x-axis. Calling the length of AD "a," the x-value of C b, and point B (c,d), we obtain:
$A: 0,0 \\ B: c,d \\ C: b,d \\ D: a,0 $
