Please helppp i will mark brainlistt

Find the length of the normal and the angle it makes with the positive x-axis. (see pictured below)

Which of these side lengths could form a triangle a) 2 cm , 2 cm , 4 cm b) 3 cm , 5 cm , 10 cm c) 3 cm , 4 cm , 5 cm d) 4 cm , 8 cm , 15 cm

Find the volume of the wedge cut from the first octant by the cylinder z=12-3y^2 and the plane x+y=2.