Finding the Fourth Proportional to 1,081.40, 1,620.69 and 487.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.40 : 1,620.69 = 487.98 : x
2. Step 2: Convert to fraction form
   1,081.40/1,620.69 = 487.98/x
3. Step 3: Cross multiply
   1,081.40x = 1,620.69 × 487.98
4. Step 4: Simplify right side
   1,081.40x = 790,864.31
5. Step 5: Solve for x
   x = 790,864.31/1,081.40
6. Step 6: Final answer
   x = 731.33