Answer: 12 units
Step-by-step explanation
Based on the diagram we can see that:
Count out the number of spaces, or subtract coordinates to determine those lengths. Then use the pythagorean theorem
to determine the hypotenuse is 5 units long.
Triangle GHI is a 3-4-5 right triangle.
Add up the exterior sides to get the perimeter.
3+4+5 = 12 units is the perimeter