A painter uses a trestle to stand on in order to paint a ceiling. It consists of 2 stepladders connected by a 4 metre long plank.The inner feet of the 2 stepladders are 3 metre apart, and each ladder has slopping sides of 2.5 metres. How high of the ground is the plank?

Answer 1

As usual, draw a diagram.
Assuming the plank is just long enough to join the tops of the ladders, there is a 1/2 m overlap on each end, above the sloping side. So, the height is

√(2.5^2 - .5^2)