It is (c) NML Because MN and ML is the vertex and the point meeting is M which is the angle. The M is the angle because the common letter of both vertex is the letter M
Well the volume of a cube is lbh that is length×breath×height which is given to be equal to 672.5cm3 thus lbh=672.5cm3 lb×10cm=672.5cm3 (putting value of h) solve and u obtain the Base area! (lb)