Finding the Fourth Proportional to 402,666.72, 555,680.43 and 221,381.74

Step by Step Solution

1. Step 1: Write the proportion equation
   402,666.72 : 555,680.43 = 221,381.74 : x
2. Step 2: Convert to fraction form
   402,666.72/555,680.43 = 221,381.74/x
3. Step 3: Cross multiply
   402,666.72x = 555,680.43 × 221,381.74
4. Step 4: Simplify right side
   402,666.72x = 123,017,500,477.35
5. Step 5: Solve for x
   x = 123,017,500,477.35/402,666.72
6. Step 6: Final answer
   x = 305,507.00