100 POINTS! Let d be the distance across the river and let x be the distance from the starting point to the opposite bank of the river.

Answer: 135 ft
Step-by-step explanation: In the ratio 60 ft to 20 ft, 60 is three times as long as 20, so in the ratio d to 45 ft we must multiply 45 by 3 to get the answer of 135ft.