We are given a right angled triangle with one side of unknown length. The shortest side is 3cm long, and the longest side is 5cm long. Calculate the remaining side.

This is a classic question testing your understanding of Pythagoras' Theorem. This is an equation which shows us the relationship between the 3 sides of a right angled triangle : a² + b² = c². a and b are the shorter sides, while c is the longest (the hypotenuse).For this question, we have a and c, but not b. If we subtract a from the left side of the equation and add it to the right side, we have b² = c² - a². Now we can fill in our values: b² = 5² - 3², or b² = 16. Now we take the square root of both sides, and find that b = 4cm.