Finding the Fourth Proportional to 12,128.82, 16,718.70 and 11,111.88

Step by Step Solution

1. Step 1: Write the proportion equation
   12,128.82 : 16,718.70 = 11,111.88 : x
2. Step 2: Convert to fraction form
   12,128.82/16,718.70 = 11,111.88/x
3. Step 3: Cross multiply
   12,128.82x = 16,718.70 × 11,111.88
4. Step 4: Simplify right side
   12,128.82x = 185,776,188.16
5. Step 5: Solve for x
   x = 185,776,188.16/12,128.82
6. Step 6: Final answer
   x = 15,316.92