Hello FailCalculusDraw a diagram showing the pole and the person as vertical straight lines, the ground as a horizontal line and then a diagonal line from the top of the pole through the top of the person's head to the ground.

You then have two similar triangles, where the horizontal distance from the man to the pole is of the distance of the man from the tip of his shadow. So the sides of the triangles are in the ratio . So the height of the pole the height of the man.

Can you continue from here?

Grandad