Finding the Fourth Proportional to 7,123.68, 9,831.12 and 3,980.10

Step by Step Solution

1. Step 1: Write the proportion equation
   7,123.68 : 9,831.12 = 3,980.10 : x
2. Step 2: Convert to fraction form
   7,123.68/9,831.12 = 3,980.10/x
3. Step 3: Cross multiply
   7,123.68x = 9,831.12 × 3,980.10
4. Step 4: Simplify right side
   7,123.68x = 39,128,840.71
5. Step 5: Solve for x
   x = 39,128,840.71/7,123.68
6. Step 6: Final answer
   x = 5,492.78