Answer:
diagonal is 17 cm
Step-by-step explanation:
use pathagorean theorem
you have a = 8, b= 15
c is the diagonal of the rectangle (rectangle has 90deg angles)
c^2 = a^2 + b^2
c^2 = 8^2 + 15^2
c^2 = 64 + 225
c^2 = 289
take square root
c = 17
hope this helps