Finding the Fourth Proportional to 887.55, 1,222.71 and 621.50

Step by Step Solution

1. Step 1: Write the proportion equation
   887.55 : 1,222.71 = 621.50 : x
2. Step 2: Convert to fraction form
   887.55/1,222.71 = 621.50/x
3. Step 3: Cross multiply
   887.55x = 1,222.71 × 621.50
4. Step 4: Simplify right side
   887.55x = 759,908.15
5. Step 5: Solve for x
   x = 759,908.15/887.55
6. Step 6: Final answer
   x = 856.19