Finding the Fourth Proportional to 13,215.93, 18,238.56 and 7,909.71

Step by Step Solution

1. Step 1: Write the proportion equation
   13,215.93 : 18,238.56 = 7,909.71 : x
2. Step 2: Convert to fraction form
   13,215.93/18,238.56 = 7,909.71/x
3. Step 3: Cross multiply
   13,215.93x = 18,238.56 × 7,909.71
4. Step 4: Simplify right side
   13,215.93x = 144,261,720.42
5. Step 5: Solve for x
   x = 144,261,720.42/13,215.93
6. Step 6: Final answer
   x = 10,915.74