A golfer hits an errant tee shot that lands in the rough A m

A golfer hits an errant tee shot that lands in the rough. A marker in the center of the fairway is 100yards from the center of the green. While standing on the marker and facing the green, the golfer turns 115° towards his ball. He then paces off 45 yards to his ball. How far is the ball from the center of the green?

We have to use law of cosine here

d²=100²+ 45²-2(100)(45)cos 115