Finding the Fourth Proportional to 20,736.72, 31,117.98 and 8,424.72

Step by Step Solution

1. Step 1: Write the proportion equation
   20,736.72 : 31,117.98 = 8,424.72 : x
2. Step 2: Convert to fraction form
   20,736.72/31,117.98 = 8,424.72/x
3. Step 3: Cross multiply
   20,736.72x = 31,117.98 × 8,424.72
4. Step 4: Simplify right side
   20,736.72x = 262,160,268.47
5. Step 5: Solve for x
   x = 262,160,268.47/20,736.72
6. Step 6: Final answer
   x = 12,642.32