Finding the Fourth Proportional to 139,899.20, 209,807.14 and 51,131.98

Step by Step Solution

1. Step 1: Write the proportion equation
   139,899.20 : 209,807.14 = 51,131.98 : x
2. Step 2: Convert to fraction form
   139,899.20/209,807.14 = 51,131.98/x
3. Step 3: Cross multiply
   139,899.20x = 209,807.14 × 51,131.98
4. Step 4: Simplify right side
   139,899.20x = 10,727,854,486.34
5. Step 5: Solve for x
   x = 10,727,854,486.34/139,899.20
6. Step 6: Final answer
   x = 76,682.74