Finding the Fourth Proportional to 1,560.58, 2,153.88 and 931.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,560.58 : 2,153.88 = 931.15 : x
2. Step 2: Convert to fraction form
   1,560.58/2,153.88 = 931.15/x
3. Step 3: Cross multiply
   1,560.58x = 2,153.88 × 931.15
4. Step 4: Simplify right side
   1,560.58x = 2,005,585.36
5. Step 5: Solve for x
   x = 2,005,585.36/1,560.58
6. Step 6: Final answer
   x = 1,285.15