Finding the Fourth Proportional to 1,061.10, 1,591.08 and 320.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,061.10 : 1,591.08 = 320.61 : x
2. Step 2: Convert to fraction form
   1,061.10/1,591.08 = 320.61/x
3. Step 3: Cross multiply
   1,061.10x = 1,591.08 × 320.61
4. Step 4: Simplify right side
   1,061.10x = 510,116.16
5. Step 5: Solve for x
   x = 510,116.16/1,061.10
6. Step 6: Final answer
   x = 480.74