Answer: y is equal to 3.89,
Step-by-step explanation: This question can be solved using the theorem of the power of a point.
The power of a point Theorem states that if a two lines intercept at a point that is intersect with the center of the circle, the lines will create either one segment (S) or two segments (s1 and s2). And the multiplication of each segment equal, which is s1s2 for line one is equal to s1s2 for line two.
Therefore for the diagram.
Using the power of a point Theorem;
9 ×y = 5 × 7
9y = 35
Therefore;
y = 35 ÷ 9 = 3.88889
y = 3.89