Finding the Fourth Proportional to 2,621.71, 3,930.86 and 1,215.54

Step by Step Solution

1. Step 1: Write the proportion equation
   2,621.71 : 3,930.86 = 1,215.54 : x
2. Step 2: Convert to fraction form
   2,621.71/3,930.86 = 1,215.54/x
3. Step 3: Cross multiply
   2,621.71x = 3,930.86 × 1,215.54
4. Step 4: Simplify right side
   2,621.71x = 4,778,111.49
5. Step 5: Solve for x
   x = 4,778,111.49/2,621.71
6. Step 6: Final answer
   x = 1,822.52