Finding the Fourth Proportional to 2,128.50, 3,188.70 and 1,664.10

Step by Step Solution

1. Step 1: Write the proportion equation
   2,128.50 : 3,188.70 = 1,664.10 : x
2. Step 2: Convert to fraction form
   2,128.50/3,188.70 = 1,664.10/x
3. Step 3: Cross multiply
   2,128.50x = 3,188.70 × 1,664.10
4. Step 4: Simplify right side
   2,128.50x = 5,306,315.67
5. Step 5: Solve for x
   x = 5,306,315.67/2,128.50
6. Step 6: Final answer
   x = 2,492.98