Let the coordinates of the treasure be (x,y).
Let

= distance from the rock to the treasure.
Let

= distance from the tree to the treasure.


We want

= 5/9 in order to locate the treasure.
Note that 5/9 = 0.556 (approx)
Test (11.4, 14.2)
d1 = 14.8, d2 = 8.2, d1/d2 = 1.8 Incorrect
Test (7.6, 8.8)
d1 = 8.2, d2 = 14.8, d1/d2 = 0.554 Correct
Test (5.7, 7.5)
d1 = 6.13, d2 = 16.98, d1/d2 = 0.36 Incorrect
Test (10.2, 12.6)
d1 = 12.8, d2 = 10.2, d1/d2 = 1.255 Incorrect
Answer:
The correct answer is (7.6, 8.8)