Finding the Fourth Proportional to 1,561.95, 2,155.25 and 898.70

Step by Step Solution

1. Step 1: Write the proportion equation
   1,561.95 : 2,155.25 = 898.70 : x
2. Step 2: Convert to fraction form
   1,561.95/2,155.25 = 898.70/x
3. Step 3: Cross multiply
   1,561.95x = 2,155.25 × 898.70
4. Step 4: Simplify right side
   1,561.95x = 1,936,907.91
5. Step 5: Solve for x
   x = 1,936,907.91/1,561.95
6. Step 6: Final answer
   x = 1,240.06