Finding the Fourth Proportional to 1,439.86, 2,157.63 and 862.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,439.86 : 2,157.63 = 862.10 : x
2. Step 2: Convert to fraction form
   1,439.86/2,157.63 = 862.10/x
3. Step 3: Cross multiply
   1,439.86x = 2,157.63 × 862.10
4. Step 4: Simplify right side
   1,439.86x = 1,860,092.82
5. Step 5: Solve for x
   x = 1,860,092.82/1,439.86
6. Step 6: Final answer
   x = 1,291.86