Respuesta :

Answer:

  • D. 8

Step-by-step explanation:

  • DC = AC = x is the radius

Using the Pythagorean theorem, find x:

  • (x + 9)² - x² = 15²
  • x² + 18x + 81 - x² = 225
  • 18x = 225 - 81
  • 18x = 144
  • x = 144/18
  • x = 8