Finding the Fourth Proportional to 1,101.60, 1,520.31 and 708.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,101.60 : 1,520.31 = 708.72 : x
2. Step 2: Convert to fraction form
   1,101.60/1,520.31 = 708.72/x
3. Step 3: Cross multiply
   1,101.60x = 1,520.31 × 708.72
4. Step 4: Simplify right side
   1,101.60x = 1,077,474.10
5. Step 5: Solve for x
   x = 1,077,474.10/1,101.60
6. Step 6: Final answer
   x = 978.10