Finding the Fourth Proportional to 12,993.12, 17,918.55 and 8,515.25

Step by Step Solution

1. Step 1: Write the proportion equation
   12,993.12 : 17,918.55 = 8,515.25 : x
2. Step 2: Convert to fraction form
   12,993.12/17,918.55 = 8,515.25/x
3. Step 3: Cross multiply
   12,993.12x = 17,918.55 × 8,515.25
4. Step 4: Simplify right side
   12,993.12x = 152,580,843.29
5. Step 5: Solve for x
   x = 152,580,843.29/12,993.12
6. Step 6: Final answer
   x = 11,743.20