Finding the Fourth Proportional to 1,639.37, 2,456.71 and 1,221.01

Step by Step Solution

1. Step 1: Write the proportion equation
   1,639.37 : 2,456.71 = 1,221.01 : x
2. Step 2: Convert to fraction form
   1,639.37/2,456.71 = 1,221.01/x
3. Step 3: Cross multiply
   1,639.37x = 2,456.71 × 1,221.01
4. Step 4: Simplify right side
   1,639.37x = 2,999,667.48
5. Step 5: Solve for x
   x = 2,999,667.48/1,639.37
6. Step 6: Final answer
   x = 1,829.77