Answer:12.64
Step-by-step explanation: Using the pythagorean therum, we can see that each side of ABCD is part of a triangle whose other legs are 4 and 1. This means that each side of ABCD squared is equal to 3 squared + 1 squared which means that each side squared is 10. So each side is equal to the square root of 10 which means each side is around 3.16. So the perimenter is around 3.16x4 = 12.64