Finding the Fourth Proportional to 1,561.30, 2,155.05 and 898.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,561.30 : 2,155.05 = 898.60 : x
2. Step 2: Convert to fraction form
   1,561.30/2,155.05 = 898.60/x
3. Step 3: Cross multiply
   1,561.30x = 2,155.05 × 898.60
4. Step 4: Simplify right side
   1,561.30x = 1,936,527.93
5. Step 5: Solve for x
   x = 1,936,527.93/1,561.30
6. Step 6: Final answer
   x = 1,240.33