Pentagon PQRST is shown on the grid a student reflected pentagon PQRST across the y-axis to create hexagon P'Q'R'S'T'

To reflect a shape across the y-axis, we need to change the sign of the x-coordinates while keeping the y-coordinates the same.

So, reflecting pentagon PQRST across the y-axis would give us the following image:

Hexagon P'Q'R'S'T'

P' = (-P, y)

Q' = (-Q, y)

R' = (-R, y)

S' = (-S, y)

T' = (-T, y)

In this case, since we do not have specific values for the coordinates of pentagon PQRST, we cannot provide exact values for hexagon P'Q'R'S'T'. We can only describe the general rule for reflecting a shape across the y-axis.