Finding the Fourth Proportional to 1,562.21, 2,155.83 and 863.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,562.21 : 2,155.83 = 863.60 : x
2. Step 2: Convert to fraction form
   1,562.21/2,155.83 = 863.60/x
3. Step 3: Cross multiply
   1,562.21x = 2,155.83 × 863.60
4. Step 4: Simplify right side
   1,562.21x = 1,861,774.79
5. Step 5: Solve for x
   x = 1,861,774.79/1,562.21
6. Step 6: Final answer
   x = 1,191.76