Finding the Fourth Proportional to 2,216.77, 3,318.71 and 1,289.50

Step by Step Solution

1. Step 1: Write the proportion equation
   2,216.77 : 3,318.71 = 1,289.50 : x
2. Step 2: Convert to fraction form
   2,216.77/3,318.71 = 1,289.50/x
3. Step 3: Cross multiply
   2,216.77x = 3,318.71 × 1,289.50
4. Step 4: Simplify right side
   2,216.77x = 4,279,476.55
5. Step 5: Solve for x
   x = 4,279,476.55/2,216.77
6. Step 6: Final answer
   x = 1,930.50