Finding the Fourth Proportional to 21,111.39, 29,128.91 and 12,612.16

Step by Step Solution

1. Step 1: Write the proportion equation
   21,111.39 : 29,128.91 = 12,612.16 : x
2. Step 2: Convert to fraction form
   21,111.39/29,128.91 = 12,612.16/x
3. Step 3: Cross multiply
   21,111.39x = 29,128.91 × 12,612.16
4. Step 4: Simplify right side
   21,111.39x = 367,378,473.55
5. Step 5: Solve for x
   x = 367,378,473.55/21,111.39
6. Step 6: Final answer
   x = 17,401.91