Finding the Fourth Proportional to 21,081.81, 29,089.40 and 12,587.37

Step by Step Solution

1. Step 1: Write the proportion equation
   21,081.81 : 29,089.40 = 12,587.37 : x
2. Step 2: Convert to fraction form
   21,081.81/29,089.40 = 12,587.37/x
3. Step 3: Cross multiply
   21,081.81x = 29,089.40 × 12,587.37
4. Step 4: Simplify right side
   21,081.81x = 366,158,868.86
5. Step 5: Solve for x
   x = 366,158,868.86/21,081.81
6. Step 6: Final answer
   x = 17,368.47