Finding the Fourth Proportional to 11,388.72, 17,075.61 and 5,142.09

Step by Step Solution

1. Step 1: Write the proportion equation
   11,388.72 : 17,075.61 = 5,142.09 : x
2. Step 2: Convert to fraction form
   11,388.72/17,075.61 = 5,142.09/x
3. Step 3: Cross multiply
   11,388.72x = 17,075.61 × 5,142.09
4. Step 4: Simplify right side
   11,388.72x = 87,804,323.42
5. Step 5: Solve for x
   x = 87,804,323.42/11,388.72
6. Step 6: Final answer
   x = 7,709.76