Finding the Fourth Proportional to 139,919.78, 209,814.05 and 51,111.18

Step by Step Solution

1. Step 1: Write the proportion equation
   139,919.78 : 209,814.05 = 51,111.18 : x
2. Step 2: Convert to fraction form
   139,919.78/209,814.05 = 51,111.18/x
3. Step 3: Cross multiply
   139,919.78x = 209,814.05 × 51,111.18
4. Step 4: Simplify right side
   139,919.78x = 10,723,843,612.19
5. Step 5: Solve for x
   x = 10,723,843,612.19/139,919.78
6. Step 6: Final answer
   x = 76,642.80