Finding the Fourth Proportional to 1,561.37, 2,155.05 and 898.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,561.37 : 2,155.05 = 898.61 : x
2. Step 2: Convert to fraction form
   1,561.37/2,155.05 = 898.61/x
3. Step 3: Cross multiply
   1,561.37x = 2,155.05 × 898.61
4. Step 4: Simplify right side
   1,561.37x = 1,936,538.71
5. Step 5: Solve for x
   x = 1,936,538.71/1,561.37
6. Step 6: Final answer
   x = 1,240.28