Finding the Fourth Proportional to 11,142.08, 15,386.40 and 8,342.72

Step by Step Solution

1. Step 1: Write the proportion equation
   11,142.08 : 15,386.40 = 8,342.72 : x
2. Step 2: Convert to fraction form
   11,142.08/15,386.40 = 8,342.72/x
3. Step 3: Cross multiply
   11,142.08x = 15,386.40 × 8,342.72
4. Step 4: Simplify right side
   11,142.08x = 128,364,427.01
5. Step 5: Solve for x
   x = 128,364,427.01/11,142.08
6. Step 6: Final answer
   x = 11,520.69