Finding the Fourth Proportional to 405,609.72, 608,428.55 and 139,367.98

Step by Step Solution

1. Step 1: Write the proportion equation
   405,609.72 : 608,428.55 = 139,367.98 : x
2. Step 2: Convert to fraction form
   405,609.72/608,428.55 = 139,367.98/x
3. Step 3: Cross multiply
   405,609.72x = 608,428.55 × 139,367.98
4. Step 4: Simplify right side
   405,609.72x = 84,795,457,987.83
5. Step 5: Solve for x
   x = 84,795,457,987.83/405,609.72
6. Step 6: Final answer
   x = 209,056.77