X,Y are two planes, X intersect Y = AB ;the square ABCD is drawn in plane X, N is the midpoint of AB, M is the midpoint of CD, draw ML perpindicular to plane Y to intersect it at L.
i) Prove that AB is perpindicular to plane (NML).
ii) If m(L-AB-M)= 60 degrees, prove that the plane (AML) is perpindicular to the plane (BML).
i) Prove that AB is perpindicular to plane (NML).
ii) If m(L-AB-M)= 60 degrees, prove that the plane (AML) is perpindicular to the plane (BML).