Finding the Fourth Proportional to 404,456.28, 558,111.78 and 390,867.72

Step by Step Solution

1. Step 1: Write the proportion equation
   404,456.28 : 558,111.78 = 390,867.72 : x
2. Step 2: Convert to fraction form
   404,456.28/558,111.78 = 390,867.72/x
3. Step 3: Cross multiply
   404,456.28x = 558,111.78 × 390,867.72
4. Step 4: Simplify right side
   404,456.28x = 218,147,878,953.74
5. Step 5: Solve for x
   x = 218,147,878,953.74/404,456.28
6. Step 6: Final answer
   x = 539,360.84