Finding the Fourth Proportional to 256,679.88, 384,941.34 and 90,429

Step by Step Solution

1. Step 1: Write the proportion equation
   256,679.88 : 384,941.34 = 90,429 : x
2. Step 2: Convert to fraction form
   256,679.88/384,941.34 = 90,429/x
3. Step 3: Cross multiply
   256,679.88x = 384,941.34 × 90,429
4. Step 4: Simplify right side
   256,679.88x = 34,809,860,434.86
5. Step 5: Solve for x
   x = 34,809,860,434.86/256,679.88
6. Step 6: Final answer
   x = 135,615.85