Finding the Fourth Proportional to 13,404.84, 18,499.28 and 8,921.40

Step by Step Solution

1. Step 1: Write the proportion equation
   13,404.84 : 18,499.28 = 8,921.40 : x
2. Step 2: Convert to fraction form
   13,404.84/18,499.28 = 8,921.40/x
3. Step 3: Cross multiply
   13,404.84x = 18,499.28 × 8,921.40
4. Step 4: Simplify right side
   13,404.84x = 165,039,476.59
5. Step 5: Solve for x
   x = 165,039,476.59/13,404.84
6. Step 6: Final answer
   x = 12,311.93