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Challenge 356: Four Equal Pieces

How can you use just two perpendicular straight lines to divide these shapes into four equal pieces?

(i) You can probably see straight away how you could use two straight, perpendicular lines to divide a square into four pieces of equal area. But how many ways are there to do this?

(ii) A slightly trickier problem arises if we have to use two straight, perpendicular lines to divide an equilateral triangle into four pieces of equal area. Find a way to do this and describe precisely where to draw the two straight lines.

(iii) More challenging still! Find a way to use two straight, perpendicular lines to divide a regular pentagon into four pieces of equal area and describe precisely where to draw the two straight lines.