Finding the Fourth Proportional to 3,390, 5,085.72 and 1,081.68

Step by Step Solution

1. Step 1: Write the proportion equation
   3,390 : 5,085.72 = 1,081.68 : x
2. Step 2: Convert to fraction form
   3,390/5,085.72 = 1,081.68/x
3. Step 3: Cross multiply
   3,390x = 5,085.72 × 1,081.68
4. Step 4: Simplify right side
   3,390x = 5,501,121.61
5. Step 5: Solve for x
   x = 5,501,121.61/3,390
6. Step 6: Final answer
   x = 1,622.75