Finding the Fourth Proportional to 87,128.71, 120,219.25 and 56,958.43

Step by Step Solution

1. Step 1: Write the proportion equation
   87,128.71 : 120,219.25 = 56,958.43 : x
2. Step 2: Convert to fraction form
   87,128.71/120,219.25 = 56,958.43/x
3. Step 3: Cross multiply
   87,128.71x = 120,219.25 × 56,958.43
4. Step 4: Simplify right side
   87,128.71x = 6,847,499,735.78
5. Step 5: Solve for x
   x = 6,847,499,735.78/87,128.71
6. Step 6: Final answer
   x = 78,590.62