In the diagram below, find the value of x to the nearest tenth.?

Join the center and one end of the chord with length 11, a right-angled triangle is formed.

In the right-angled triangle :
x² = √[3.6² + (11/2)²]
x² = √[12.96 + 30.25]
x² = √43.21
x ≈ 6.6

...... The answer is : b) 6.6