Finding the Fourth Proportional to 10,200.78, 15,286.80 and 8,111.51

Step by Step Solution

1. Step 1: Write the proportion equation
   10,200.78 : 15,286.80 = 8,111.51 : x
2. Step 2: Convert to fraction form
   10,200.78/15,286.80 = 8,111.51/x
3. Step 3: Cross multiply
   10,200.78x = 15,286.80 × 8,111.51
4. Step 4: Simplify right side
   10,200.78x = 123,999,042.38
5. Step 5: Solve for x
   x = 123,999,042.38/10,200.78
6. Step 6: Final answer
   x = 12,155.84