Respuesta :

Answer:

√32 or 4√2 or 5.657 (3 d.p.)

Step-by-step explanation:

  • Use Pythagoras’ Theorem
  • d² + 7² = 9²
  • Evaluate the known squares
  • d² + 49 = 81
  • Subtract 49 from both sides to make d² the subject
  • d² = 81 - 49 = 32
  • d = √32 = 4√2 = 5.657 (3 d.p.)