Finding the Fourth Proportional to 139,221.99, 208,359.54 and 85,947.48

Step by Step Solution

1. Step 1: Write the proportion equation
   139,221.99 : 208,359.54 = 85,947.48 : x
2. Step 2: Convert to fraction form
   139,221.99/208,359.54 = 85,947.48/x
3. Step 3: Cross multiply
   139,221.99x = 208,359.54 × 85,947.48
4. Step 4: Simplify right side
   139,221.99x = 17,907,977,396.96
5. Step 5: Solve for x
   x = 17,907,977,396.96/139,221.99
6. Step 6: Final answer
   x = 128,628.94