You’ve no doubt heard the carpentry proverb “Measure twice, cut once” and may even have made it a mantra for your own projects. But unless you know how to use a tape measure and correctly read its ...

So you have a circle. What is the area of that circle? Surely everyone remembers that the area of a circle is: Where Pi (π) is of course the number and r is the radius of the circle. Where does this ...