Finding the Fourth Proportional to 280,705.86, 421,085.37 and 78,315.42

Step by Step Solution

1. Step 1: Write the proportion equation
   280,705.86 : 421,085.37 = 78,315.42 : x
2. Step 2: Convert to fraction form
   280,705.86/421,085.37 = 78,315.42/x
3. Step 3: Cross multiply
   280,705.86x = 421,085.37 × 78,315.42
4. Step 4: Simplify right side
   280,705.86x = 32,977,477,607.41
5. Step 5: Solve for x
   x = 32,977,477,607.41/280,705.86
6. Step 6: Final answer
   x = 117,480.55