Finding the Fourth Proportional to 139,020, 208,005.12 and 86,182.08

Step by Step Solution

1. Step 1: Write the proportion equation
   139,020 : 208,005.12 = 86,182.08 : x
2. Step 2: Convert to fraction form
   139,020/208,005.12 = 86,182.08/x
3. Step 3: Cross multiply
   139,020x = 208,005.12 × 86,182.08
4. Step 4: Simplify right side
   139,020x = 17,926,313,892.25
5. Step 5: Solve for x
   x = 17,926,313,892.25/139,020
6. Step 6: Final answer
   x = 128,947.73