Im not sure if there is an equation.....

Anyways, we can first find the area of the square. That is 0.5^2, which is 0.25. The area of the triangles are 0.5(0.4)(2), which is 0.4. Add those together, and you get 0.65.

EDIT: THanks guest, i need to practice my addtion, lol

:)