Answer:
14.76
Explanation:
First find the length of the diagonal across the bottom using the Pythagorean theorem
a^2 + b^2 = c^2 where a and b are the legs and c is the hypotenuse
12^2+5^2 = c^2
144+25 = c^2
169 = c^2
Take the square root of each side
sqrt(169) = sqrt(c^2)
13 = c
Then find the length of the diagonal across the middle using the Pythagorean theorem
7^2 + c^2 = d^2
7^2 + 13^2 = d^2
49+ 169 = d^2
218 = d^2
Take the square root of each side
sqrt(218) = sqrt(d^2)
14.76482306 = d
To the nearest thousandth
14.76