(Solved): A 0.135kg book rests at an angle against one side of a bookshelf. The magnitude and direction of ...

A $0.135\mathrm{kg}$ book rests at an angle against one side of a bookshelf. The magnitude and direction of the total force exerted on the book by the left side of the bookshelf are given by $?F_{\mathrm{L}}?=0.815\mathrm{N}{?}_{\mathrm{L}}=63.0^{?}$ What must the magnitude $?F_{\mathrm{B}}?$ and direction ${?}_{\mathrm{B}}$ of the total force exerted on the book by the bottom of the bookshelf be in order for the book to remain in this position? $?F_{\mathrm{B}}?=$ $\mathrm{N}$