Finding the Fourth Proportional to 402,415.86, 555,300.64 and 221,118.42

Step by Step Solution

1. Step 1: Write the proportion equation
   402,415.86 : 555,300.64 = 221,118.42 : x
2. Step 2: Convert to fraction form
   402,415.86/555,300.64 = 221,118.42/x
3. Step 3: Cross multiply
   402,415.86x = 555,300.64 × 221,118.42
4. Step 4: Simplify right side
   402,415.86x = 122,787,200,141.79
5. Step 5: Solve for x
   x = 122,787,200,141.79/402,415.86
6. Step 6: Final answer
   x = 305,125.15