Finding the Fourth Proportional to 21,005.72, 28,988.56 and 12,054.86

Step by Step Solution

1. Step 1: Write the proportion equation
   21,005.72 : 28,988.56 = 12,054.86 : x
2. Step 2: Convert to fraction form
   21,005.72/28,988.56 = 12,054.86/x
3. Step 3: Cross multiply
   21,005.72x = 28,988.56 × 12,054.86
4. Step 4: Simplify right side
   21,005.72x = 349,453,032.40
5. Step 5: Solve for x
   x = 349,453,032.40/21,005.72
6. Step 6: Final answer
   x = 16,636.09