Answer:
8.7 units
Step-by-step explanation:
Given is a right angled triangle (because the segment with 5 units length is tangent to circle. Tangent is perpendicular to RADIUS or diameter)
Let the length of the diameter be d units
By Pythagoras Theorem:
[tex]d = \sqrt{ {10}^{2} - {5}^{2} } \\ = \sqrt{100 - 25} \\ = \sqrt{75} \\ = 8.66025404 \\ = 8.7 \: units[/tex]