Finding the Fourth Proportional to 100,005.12, 138,006.72 and 55,293.12

Step by Step Solution

1. Step 1: Write the proportion equation
   100,005.12 : 138,006.72 = 55,293.12 : x
2. Step 2: Convert to fraction form
   100,005.12/138,006.72 = 55,293.12/x
3. Step 3: Cross multiply
   100,005.12x = 138,006.72 × 55,293.12
4. Step 4: Simplify right side
   100,005.12x = 7,630,822,129.77
5. Step 5: Solve for x
   x = 7,630,822,129.77/100,005.12
6. Step 6: Final answer
   x = 76,304.31