Answer:
172.5m
Step-by-step explanation:
This can be addressed by forming a ratio with the known and using that ration to address the unkown.
6m : 4m
This gives us a ratio of 1.5. i.e, the real object is 1.5x the image.
So if the image is 115m, the real object will be 115 * 1.5 = 172.5m