Finding the Fourth Proportional to 13,144.44, 18,139.34 and 8,428.72

Step by Step Solution

1. Step 1: Write the proportion equation
   13,144.44 : 18,139.34 = 8,428.72 : x
2. Step 2: Convert to fraction form
   13,144.44/18,139.34 = 8,428.72/x
3. Step 3: Cross multiply
   13,144.44x = 18,139.34 × 8,428.72
4. Step 4: Simplify right side
   13,144.44x = 152,891,417.84
5. Step 5: Solve for x
   x = 152,891,417.84/13,144.44
6. Step 6: Final answer
   x = 11,631.64