Finding the Fourth Proportional to 21,117.72, 31,672.08 and 7,078.80

Step by Step Solution

1. Step 1: Write the proportion equation
   21,117.72 : 31,672.08 = 7,078.80 : x
2. Step 2: Convert to fraction form
   21,117.72/31,672.08 = 7,078.80/x
3. Step 3: Cross multiply
   21,117.72x = 31,672.08 × 7,078.80
4. Step 4: Simplify right side
   21,117.72x = 224,200,319.90
5. Step 5: Solve for x
   x = 224,200,319.90/21,117.72
6. Step 6: Final answer
   x = 10,616.69