# Solution to the Three Congruent Squares in a Rectangle Puzzle +-- {.image} [[ThreeCongruentSquaresinaRectangle.png:pic]] > What fraction of the rectangle is covered by these three identical squares? =-- ## Solution by [[Similar Triangles]] +-- {.image} [[ThreeCongruentSquaresinaRectangleLabelled.png:pic]] =-- With the points labelled as in the diagram, triangles $E C D$ and $A B D$ are [[similar]]. The length scale factor can be seen to be $3$ (from $E C D$ to $A B D$) by considering $E C$ and $A B$. Therefore $D C$ is one third of $D B$ and so $\frac{2}{3}$rds of the rectangle is shaded.