# Solution to the A Semi-Circle and Quarter Circle in a Square Puzzle +-- {.image} [[ASemiCircleandQuarterCircleinaSquare.png:pic]] > What's the area of the square? =-- ## Solution by [[Area of a Circle]] and [[Lengths in a Square]] +-- {.image} [[ASemiCircleandQuarterCircleinaSquareLabelled.png:pic]] =-- Using the [[area of a circle]], the radius of the quarter circle is $2$ and of the semi-circle is $\sqrt{2}$. This means that the point labelled $B$ in the above is the centre of a square with side length $2\sqrt{2}$ and diagonal $4$. Its area is therefore $8$.