Finding the Fourth Proportional to 2,102.31, 2,901.20 and 1,217.79

Step by Step Solution

1. Step 1: Write the proportion equation
   2,102.31 : 2,901.20 = 1,217.79 : x
2. Step 2: Convert to fraction form
   2,102.31/2,901.20 = 1,217.79/x
3. Step 3: Cross multiply
   2,102.31x = 2,901.20 × 1,217.79
4. Step 4: Simplify right side
   2,102.31x = 3,533,040.89
5. Step 5: Solve for x
   x = 3,533,040.89/2,102.31
6. Step 6: Final answer
   x = 1,680.56