Finding the Fourth Proportional to 883.89, 1,217.52 and 840.15

Step by Step Solution

1. Step 1: Write the proportion equation
   883.89 : 1,217.52 = 840.15 : x
2. Step 2: Convert to fraction form
   883.89/1,217.52 = 840.15/x
3. Step 3: Cross multiply
   883.89x = 1,217.52 × 840.15
4. Step 4: Simplify right side
   883.89x = 1,022,899.43
5. Step 5: Solve for x
   x = 1,022,899.43/883.89
6. Step 6: Final answer
   x = 1,157.27