Finding the Fourth Proportional to 3,856.77, 5,787.76 and 1,665.72

Step by Step Solution

1. Step 1: Write the proportion equation
   3,856.77 : 5,787.76 = 1,665.72 : x
2. Step 2: Convert to fraction form
   3,856.77/5,787.76 = 1,665.72/x
3. Step 3: Cross multiply
   3,856.77x = 5,787.76 × 1,665.72
4. Step 4: Simplify right side
   3,856.77x = 9,640,797.89
5. Step 5: Solve for x
   x = 9,640,797.89/3,856.77
6. Step 6: Final answer
   x = 2,499.71