Finding the Fourth Proportional to 10,980.72, 15,138.72 and 9,085.32

Step by Step Solution

1. Step 1: Write the proportion equation
   10,980.72 : 15,138.72 = 9,085.32 : x
2. Step 2: Convert to fraction form
   10,980.72/15,138.72 = 9,085.32/x
3. Step 3: Cross multiply
   10,980.72x = 15,138.72 × 9,085.32
4. Step 4: Simplify right side
   10,980.72x = 137,540,115.59
5. Step 5: Solve for x
   x = 137,540,115.59/10,980.72
6. Step 6: Final answer
   x = 12,525.60