Finding the Fourth Proportional to 21,003.98, 28,989.69 and 12,057.53

Step by Step Solution

1. Step 1: Write the proportion equation
   21,003.98 : 28,989.69 = 12,057.53 : x
2. Step 2: Convert to fraction form
   21,003.98/28,989.69 = 12,057.53/x
3. Step 3: Cross multiply
   21,003.98x = 28,989.69 × 12,057.53
4. Step 4: Simplify right side
   21,003.98x = 349,544,056.87
5. Step 5: Solve for x
   x = 349,544,056.87/21,003.98
6. Step 6: Final answer
   x = 16,641.80