Finding the Fourth Proportional to 21,780.12, 30,056.43 and 12,089.47

Step by Step Solution

1. Step 1: Write the proportion equation
   21,780.12 : 30,056.43 = 12,089.47 : x
2. Step 2: Convert to fraction form
   21,780.12/30,056.43 = 12,089.47/x
3. Step 3: Cross multiply
   21,780.12x = 30,056.43 × 12,089.47
4. Step 4: Simplify right side
   21,780.12x = 363,366,308.79
5. Step 5: Solve for x
   x = 363,366,308.79/21,780.12
6. Step 6: Final answer
   x = 16,683.39