I tried these problems out but I am having too much trouble

A rock dropped out into a pond sends out a circular ripple whose radius increases steadily at 6 cm/s. A toy boat floating on the ponds is 2m east and 1 m north of the spot where the rock is dropped How long does it take for the ripple to reach the boat?

A truck with a wide load, proceeding along a secondary road is approaching a tunnel with a semicircular cross section and a maximum height of 5.25m. If the load is 8m high and 3.5m high will it fit through the tunnel? Explain your answer and include your calculations.

This question I wasnt sure how to start but its worth 7 marks

An error has been made in setting out the square base of a building. the coordinates listed for the corners of the squares are (60,20), (90,120), (-10,140) and (-40,50). Which coordinate pair is incorrect? Explain your choice. What should the coordinates be ? Write a paragraph explaining what the error is, how it was detected, and how it should be corrected