Finding the Fourth Proportional to 139,123.72, 191,978.04 and 78,699.88

Step by Step Solution

1. Step 1: Write the proportion equation
   139,123.72 : 191,978.04 = 78,699.88 : x
2. Step 2: Convert to fraction form
   139,123.72/191,978.04 = 78,699.88/x
3. Step 3: Cross multiply
   139,123.72x = 191,978.04 × 78,699.88
4. Step 4: Simplify right side
   139,123.72x = 15,108,648,710.64
5. Step 5: Solve for x
   x = 15,108,648,710.64/139,123.72
6. Step 6: Final answer
   x = 108,598.65