Finding the Fourth Proportional to 21,830.16, 30,124.32 and 12,878

Step by Step Solution

1. Step 1: Write the proportion equation
   21,830.16 : 30,124.32 = 12,878 : x
2. Step 2: Convert to fraction form
   21,830.16/30,124.32 = 12,878/x
3. Step 3: Cross multiply
   21,830.16x = 30,124.32 × 12,878
4. Step 4: Simplify right side
   21,830.16x = 387,940,992.96
5. Step 5: Solve for x
   x = 387,940,992.96/21,830.16
6. Step 6: Final answer
   x = 17,770.87