Finding the Fourth Proportional to 87,321.72, 120,408.72 and 58,978.20

Step by Step Solution

1. Step 1: Write the proportion equation
   87,321.72 : 120,408.72 = 58,978.20 : x
2. Step 2: Convert to fraction form
   87,321.72/120,408.72 = 58,978.20/x
3. Step 3: Cross multiply
   87,321.72x = 120,408.72 × 58,978.20
4. Step 4: Simplify right side
   87,321.72x = 7,101,489,569.90
5. Step 5: Solve for x
   x = 7,101,489,569.90/87,321.72
6. Step 6: Final answer
   x = 81,325.58