Finding the Fourth Proportional to 287,679.72, 428,122.91 and 278,100.98

Step by Step Solution

1. Step 1: Write the proportion equation
   287,679.72 : 428,122.91 = 278,100.98 : x
2. Step 2: Convert to fraction form
   287,679.72/428,122.91 = 278,100.98/x
3. Step 3: Cross multiply
   287,679.72x = 428,122.91 × 278,100.98
4. Step 4: Simplify right side
   287,679.72x = 119,061,400,991.55
5. Step 5: Solve for x
   x = 119,061,400,991.55/287,679.72
6. Step 6: Final answer
   x = 413,867.89