Finding the Fourth Proportional to 30,978.84, 42,749.64 and 16,831.20

Step by Step Solution

1. Step 1: Write the proportion equation
   30,978.84 : 42,749.64 = 16,831.20 : x
2. Step 2: Convert to fraction form
   30,978.84/42,749.64 = 16,831.20/x
3. Step 3: Cross multiply
   30,978.84x = 42,749.64 × 16,831.20
4. Step 4: Simplify right side
   30,978.84x = 719,527,740.77
5. Step 5: Solve for x
   x = 719,527,740.77/30,978.84
6. Step 6: Final answer
   x = 23,226.43