Finding the Fourth Proportional to 139,920.29, 209,814.80 and 51,111.68

Step by Step Solution

1. Step 1: Write the proportion equation
   139,920.29 : 209,814.80 = 51,111.68 : x
2. Step 2: Convert to fraction form
   139,920.29/209,814.80 = 51,111.68/x
3. Step 3: Cross multiply
   139,920.29x = 209,814.80 × 51,111.68
4. Step 4: Simplify right side
   139,920.29x = 10,723,986,916.86
5. Step 5: Solve for x
   x = 10,723,986,916.86/139,920.29
6. Step 6: Final answer
   x = 76,643.55