Finding the Fourth Proportional to 1,561.89, 2,155.40 and 1,002.58

Step by Step Solution

1. Step 1: Write the proportion equation
   1,561.89 : 2,155.40 = 1,002.58 : x
2. Step 2: Convert to fraction form
   1,561.89/2,155.40 = 1,002.58/x
3. Step 3: Cross multiply
   1,561.89x = 2,155.40 × 1,002.58
4. Step 4: Simplify right side
   1,561.89x = 2,160,960.93
5. Step 5: Solve for x
   x = 2,160,960.93/1,561.89
6. Step 6: Final answer
   x = 1,383.56