Finding the Fourth Proportional to 13,118.16, 18,111.60 and 10,128.72

Step by Step Solution

1. Step 1: Write the proportion equation
   13,118.16 : 18,111.60 = 10,128.72 : x
2. Step 2: Convert to fraction form
   13,118.16/18,111.60 = 10,128.72/x
3. Step 3: Cross multiply
   13,118.16x = 18,111.60 × 10,128.72
4. Step 4: Simplify right side
   13,118.16x = 183,447,325.15
5. Step 5: Solve for x
   x = 183,447,325.15/13,118.16
6. Step 6: Final answer
   x = 13,984.23