Answer:
36 km
Step-by-step explanation:
We can use the Pythagorean theorem to find a
a^2 +b^2 =c^2
a^2 +12^2 = 15^2
a^2 +144=225
Subtract 144 from each side
a^2 =225-144
a^2 =81
Taking the square root of each side
a = sqrt(81) = 9
Then we need to find the perimeter
a+12+15
9+12+15
36
