A spider sits at one of the corners of a rectangular box which has sides with a length of 1 metre. It badly wants to reach an ant which sits at the centre of one of the faces of the box the furthest from the spider. What is the shortest distance that the spider needs to travel along the surface in order to have its meal?

1 answer

Draw a diagram of the box with the sides unfolded and lying flat. Now draw a straight line from spider to fly, and the distance x is

x^2 = (1/2)^2 + (3/2)^2