Finding the Fourth Proportional to 12,642.72, 18,916.56 and 11,976

Step by Step Solution

1. Step 1: Write the proportion equation
   12,642.72 : 18,916.56 = 11,976 : x
2. Step 2: Convert to fraction form
   12,642.72/18,916.56 = 11,976/x
3. Step 3: Cross multiply
   12,642.72x = 18,916.56 × 11,976
4. Step 4: Simplify right side
   12,642.72x = 226,544,722.56
5. Step 5: Solve for x
   x = 226,544,722.56/12,642.72
6. Step 6: Final answer
   x = 17,918.99