In the diagram, O is the centre of the circle with radius OC. ABCD is a cyclic quadrilateral. N is another point on the circle such that BC is parallel to ON. OE bisects chord BC at Eu GC is a tangent to the circle at C. GC and ON are produced to meet at F. C =20 DB 150 = 83 10.1 Calculate, with reasons, the size of: 10.1.10 10.1.2 D 10.1.3 Cz NNN (2) (2) (2) (4) 10.1.4 Dz 10.2 OECF is a trapezium with OF 3y and EC=2x. Using the formula below determine the length of OE in terms of x and y if the area of OECF=yx Area of a Trapezium (sum of the parallel sides) x1 height =