We can find the area of the sector of a circle with the following equation:

Where N is the angle that defines the sector of the circle. In this case, we have the following:
![\begin{gathered} N=45\degree \\ r=1\operatorname{km} \end{gathered}]()
then, using the formula for the area of the sector, we get:

therefore, the area of the sector bounded is 1/8 pi