Finding the Fourth Proportional to 1,561.88, 2,155.34 and 853.73

Step by Step Solution

1. Step 1: Write the proportion equation
   1,561.88 : 2,155.34 = 853.73 : x
2. Step 2: Convert to fraction form
   1,561.88/2,155.34 = 853.73/x
3. Step 3: Cross multiply
   1,561.88x = 2,155.34 × 853.73
4. Step 4: Simplify right side
   1,561.88x = 1,840,074.15
5. Step 5: Solve for x
   x = 1,840,074.15/1,561.88
6. Step 6: Final answer
   x = 1,178.11