Finding the Fourth Proportional to 139,429.89, 209,292.26 and 86,876.28

Step by Step Solution

1. Step 1: Write the proportion equation
   139,429.89 : 209,292.26 = 86,876.28 : x
2. Step 2: Convert to fraction form
   139,429.89/209,292.26 = 86,876.28/x
3. Step 3: Cross multiply
   139,429.89x = 209,292.26 × 86,876.28
4. Step 4: Simplify right side
   139,429.89x = 18,182,532,547.21
5. Step 5: Solve for x
   x = 18,182,532,547.21/139,429.89
6. Step 6: Final answer
   x = 130,406.27