Which expression is equivalent to 3 sqrt[2y^3] x 7 sqrt[18y], if y>0? (see picture for easier understanding)

A — 21y sqrt[20y]
B — 21y^2 sqrt[6y]
C — 63y sqrt[2y]
D — 126y^2

Thomas is using a drawing program to complete a construction. which construction could he be completing? two perpendicular lines are drawn. inscribing an equilateral triangle in a circle inscribing a square in a circle inscribing a regular pentagon in a circle inscribing a regular hexagon in a circle