# Three Stacked Squares and a Fourth Square +-- {.image} [[ThreeStackedSquaresandaFourthSquare.png:pic]] > The three small squares each have area $4$. What's the total shaded area? =-- ## Solution by [[Congruent Triangles]] +-- {.image} [[ThreeStackedSquaresandaFourthSquareLabelled.png:pic]] =-- With the points labelled as above, angles $A \hat{C} B$ and $E \hat{C} D$ are equal and so triangles $E D C$ and $A B C$ are [[congruent]]. The shaded area is therefore equivalent in area to two squares. The total shaded area is therefore $8$.