Finding the Fourth Proportional to 1,400.56, 2,100.86 and 578.74

Step by Step Solution

1. Step 1: Write the proportion equation
   1,400.56 : 2,100.86 = 578.74 : x
2. Step 2: Convert to fraction form
   1,400.56/2,100.86 = 578.74/x
3. Step 3: Cross multiply
   1,400.56x = 2,100.86 × 578.74
4. Step 4: Simplify right side
   1,400.56x = 1,215,851.72
5. Step 5: Solve for x
   x = 1,215,851.72/1,400.56
6. Step 6: Final answer
   x = 868.12