Help? Please?

Three positive point charges are arranged in a triangular pattern in a plane, as shown below. The Coulomb constant is 8.98755 x 109N.m2/C2. A.) Find the magnitude of the net electric force on the 9 nC. Answer in units of N. B.) What is the direction of this force (as angle between -180o and 180o measured from the positive x-axis, with counterclock-wise positive)? Answer in units of o.