Finding the Fourth Proportional to 139,953.40, 209,978.70 and 61,124.20

Step by Step Solution

1. Step 1: Write the proportion equation
   139,953.40 : 209,978.70 = 61,124.20 : x
2. Step 2: Convert to fraction form
   139,953.40/209,978.70 = 61,124.20/x
3. Step 3: Cross multiply
   139,953.40x = 209,978.70 × 61,124.20
4. Step 4: Simplify right side
   139,953.40x = 12,834,780,054.54
5. Step 5: Solve for x
   x = 12,834,780,054.54/139,953.40
6. Step 6: Final answer
   x = 91,707.53