Answer:
12 feet
Step-by-step explanation:
use the pythagorean theorem to figure out what the hypotenuse is
3.5^2+3.5^2=x^2
12.25+12.25=x^2
25=x^2
x=5
now that you know the hypotenuse, you can find the perimeter by adding up all the sides
3.5+3.5+5=12
