Finding the Fourth Proportional to 21,437.72, 32,131.76 and 12,680

Step by Step Solution

1. Step 1: Write the proportion equation
   21,437.72 : 32,131.76 = 12,680 : x
2. Step 2: Convert to fraction form
   21,437.72/32,131.76 = 12,680/x
3. Step 3: Cross multiply
   21,437.72x = 32,131.76 × 12,680
4. Step 4: Simplify right side
   21,437.72x = 407,430,716.80
5. Step 5: Solve for x
   x = 407,430,716.80/21,437.72
6. Step 6: Final answer
   x = 19,005.32