Finding the Fourth Proportional to 86,978.87, 120,019.62 and 51,155.81

Step by Step Solution

1. Step 1: Write the proportion equation
   86,978.87 : 120,019.62 = 51,155.81 : x
2. Step 2: Convert to fraction form
   86,978.87/120,019.62 = 51,155.81/x
3. Step 3: Cross multiply
   86,978.87x = 120,019.62 × 51,155.81
4. Step 4: Simplify right side
   86,978.87x = 6,139,700,276.89
5. Step 5: Solve for x
   x = 6,139,700,276.89/86,978.87
6. Step 6: Final answer
   x = 70,588.42