Finding the Fourth Proportional to 13,590.72, 18,792 and 12,960

Step by Step Solution

1. Step 1: Write the proportion equation
   13,590.72 : 18,792 = 12,960 : x
2. Step 2: Convert to fraction form
   13,590.72/18,792 = 12,960/x
3. Step 3: Cross multiply
   13,590.72x = 18,792 × 12,960
4. Step 4: Simplify right side
   13,590.72x = 243,544,320
5. Step 5: Solve for x
   x = 243,544,320/13,590.72
6. Step 6: Final answer
   x = 17,919.90