Give reasons for ALL statements in QUESTIONS 8, 9 and 10.
In the diagram below O is the centre of the circle. Quadrilateral ABCO is drawn with A and C on the circumference. AB is a tangent to the circle at point A and BC is a tangent to circle at point C. D is the midpoint of chord AC and AD = DC. E is the point on the circumference of the circle with centre O.
The length of:
AC = 8 cm,
OD = 3 cm,
BE = x and
AB = x + 4.
8.1 Write down the size of 
1 .(2)
8.2 Calculate the length of OA. (2)
8.3 Determine the size of  and give a reason for your answer. (2)
8.4 Calculate the value of x if x >1. (4)
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