Finding the Fourth Proportional to 21,917.12, 30,249.52 and 12,969.55

Step by Step Solution

1. Step 1: Write the proportion equation
   21,917.12 : 30,249.52 = 12,969.55 : x
2. Step 2: Convert to fraction form
   21,917.12/30,249.52 = 12,969.55/x
3. Step 3: Cross multiply
   21,917.12x = 30,249.52 × 12,969.55
4. Step 4: Simplify right side
   21,917.12x = 392,322,667.50
5. Step 5: Solve for x
   x = 392,322,667.50/21,917.12
6. Step 6: Final answer
   x = 17,900.29