Finding the Fourth Proportional to 1,561.71, 2,155.16 and 853.54

Step by Step Solution

1. Step 1: Write the proportion equation
   1,561.71 : 2,155.16 = 853.54 : x
2. Step 2: Convert to fraction form
   1,561.71/2,155.16 = 853.54/x
3. Step 3: Cross multiply
   1,561.71x = 2,155.16 × 853.54
4. Step 4: Simplify right side
   1,561.71x = 1,839,512.01
5. Step 5: Solve for x
   x = 1,839,512.01/1,561.71
6. Step 6: Final answer
   x = 1,177.89