solution for the folloing question

(i) Given a triangle ABC, the medians AD and BE form a 90 degree angle, as shown below. It is known that AC = 3 and BC = 4. Prove that 2 ACB = LABC (Hint: Consider the Pons Asinorum theorem). D E Gi) Let (1.6.-1): B (-4.5.3): C= (3.24.-7): P(3.7 0:0 (0.1.7) and R 06. -5.7) a) Determine the size of the angle between the plane Through A.B. Cand the plane through P Q R b) Given the line (1.2.3) +, 1.0), find where this line intersects the plane containing P. and R