Finding the Fourth Proportional to 279,978.54, 420,027.35 and 90,449.78

Step by Step Solution

1. Step 1: Write the proportion equation
   279,978.54 : 420,027.35 = 90,449.78 : x
2. Step 2: Convert to fraction form
   279,978.54/420,027.35 = 90,449.78/x
3. Step 3: Cross multiply
   279,978.54x = 420,027.35 × 90,449.78
4. Step 4: Simplify right side
   279,978.54x = 37,991,381,401.48
5. Step 5: Solve for x
   x = 37,991,381,401.48/279,978.54
6. Step 6: Final answer
   x = 135,693.90