Respuesta :

Using Pythagoras Theorm,
(AO)² = (AB)²+(OB)²
(17.4)²=(7)²+ r²
Therefore, Radius = 15.92 cm Approximately.
The angle the radius makes with AB is a right angle, so the Pythagorean theorem applies.
  r² = 17.4² - 7² = 253.76
  r = √253.76 ≈ 15.9