Hi there! :)
[tex]\large\boxed{\text{B. 11 cm.}}[/tex]
Begin by using Pythagorean theorem to solve for the length of the diagonal of the base:
a² + b² = c²
Use the length and width in the equation:
8² + 3² = c²
64 + 9 = c²
73 = c²
c ≈ 8.54 cm
Now, we can find the length of the diagonal of the prism using our calculated diagonal of the base and the height. Use the same equation:
(8.54)² + 7² = c²
73 + 49 = c²
122 = c²
√122 = c
c = 11.05 ≈ 11 cm. The correct answer is B.
