Finding the Fourth Proportional to 1,561.56, 2,155.06 and 898.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,561.56 : 2,155.06 = 898.60 : x
2. Step 2: Convert to fraction form
   1,561.56/2,155.06 = 898.60/x
3. Step 3: Cross multiply
   1,561.56x = 2,155.06 × 898.60
4. Step 4: Simplify right side
   1,561.56x = 1,936,536.92
5. Step 5: Solve for x
   x = 1,936,536.92/1,561.56
6. Step 6: Final answer
   x = 1,240.13