Finding the Fourth Proportional to 15,105.98, 20,772.32 and 13,113.05

Step by Step Solution

1. Step 1: Write the proportion equation
   15,105.98 : 20,772.32 = 13,113.05 : x
2. Step 2: Convert to fraction form
   15,105.98/20,772.32 = 13,113.05/x
3. Step 3: Cross multiply
   15,105.98x = 20,772.32 × 13,113.05
4. Step 4: Simplify right side
   15,105.98x = 272,388,301.35
5. Step 5: Solve for x
   x = 272,388,301.35/15,105.98
6. Step 6: Final answer
   x = 18,031.82