$\"\"$

The chords AB,CE are equidistant from P, so $\"\"$ .

Use the Pythagorean theorem to find AD.

$\"\"$ (Apply Pythagorean theorem)

$\"\"$ (Substitute $\"\"$ )

$\"\"$ (Evaluate powers)

$\"\"$ (Subtract 100 from each side)

$\"\"$ (Subtract)

$\"\"$ (Apply square root of each side) $\"\"$

$\"\"$

$\"\"$ (Apply cross product property)

$\"\"$ (Substitute $\"\"$ )

$\"\"$ . (Multiply) $\"\"$

The value of $\"\"$ .