Finding the Fourth Proportional to 2,601.72, 3,902.16 and 1,215

Step by Step Solution

1. Step 1: Write the proportion equation
   2,601.72 : 3,902.16 = 1,215 : x
2. Step 2: Convert to fraction form
   2,601.72/3,902.16 = 1,215/x
3. Step 3: Cross multiply
   2,601.72x = 3,902.16 × 1,215
4. Step 4: Simplify right side
   2,601.72x = 4,741,124.40
5. Step 5: Solve for x
   x = 4,741,124.40/2,601.72
6. Step 6: Final answer
   x = 1,822.30