Answer: d=157.5 meters
Explanation:
I used proportion for this case, since it is known that side lengths of two similar triangles are proportional.
Take 180, divide by 400 to get the proportional increase in size.
Then multiply that number by 350, since that is the corresponding side of the similar triangle.
This would be:
180/450= 0.45
0.45*350=157.5