Answer:
16.17684994
Step-by-step explanation:
First diagonal
x^2 = a^2 + b^2
x^2 = 5^2 + 6^2
x^2 = 61
x ≈ 7.810249676
Second diagonal
x^2 = a^2 + b^2
x^2 = 7.810249676^2 + 3^2
x^2 = 70
x ≈ 8.366600265
Sum of both diagonals
8.366600265 + 7.810249676
= 16.17684994
