Finding the Fourth Proportional to 128,976.06, 177,978.28 and 71,612.43

Step by Step Solution

1. Step 1: Write the proportion equation
   128,976.06 : 177,978.28 = 71,612.43 : x
2. Step 2: Convert to fraction form
   128,976.06/177,978.28 = 71,612.43/x
3. Step 3: Cross multiply
   128,976.06x = 177,978.28 × 71,612.43
4. Step 4: Simplify right side
   128,976.06x = 12,745,457,118.02
5. Step 5: Solve for x
   x = 12,745,457,118.02/128,976.06
6. Step 6: Final answer
   x = 98,820.33