Finding the Fourth Proportional to 402,978.93, 556,088.95 and 221,661.59

Step by Step Solution

1. Step 1: Write the proportion equation
   402,978.93 : 556,088.95 = 221,661.59 : x
2. Step 2: Convert to fraction form
   402,978.93/556,088.95 = 221,661.59/x
3. Step 3: Cross multiply
   402,978.93x = 556,088.95 × 221,661.59
4. Step 4: Simplify right side
   402,978.93x = 123,263,560,838.43
5. Step 5: Solve for x
   x = 123,263,560,838.43/402,978.93
6. Step 6: Final answer
   x = 305,880.91