Finding the Fourth Proportional to 13,389.03, 18,342.72 and 12,890.48

Step by Step Solution

1. Step 1: Write the proportion equation
   13,389.03 : 18,342.72 = 12,890.48 : x
2. Step 2: Convert to fraction form
   13,389.03/18,342.72 = 12,890.48/x
3. Step 3: Cross multiply
   13,389.03x = 18,342.72 × 12,890.48
4. Step 4: Simplify right side
   13,389.03x = 236,446,373.59
5. Step 5: Solve for x
   x = 236,446,373.59/13,389.03
6. Step 6: Final answer
   x = 17,659.71