Finding the Fourth Proportional to 287,904.72, 397,336.56 and 215,181.12

Step by Step Solution

1. Step 1: Write the proportion equation
   287,904.72 : 397,336.56 = 215,181.12 : x
2. Step 2: Convert to fraction form
   287,904.72/397,336.56 = 215,181.12/x
3. Step 3: Cross multiply
   287,904.72x = 397,336.56 × 215,181.12
4. Step 4: Simplify right side
   287,904.72x = 85,499,325,997.75
5. Step 5: Solve for x
   x = 85,499,325,997.75/287,904.72
6. Step 6: Final answer
   x = 296,970.91