Finding the Fourth Proportional to 20,502.72, 30,683.61 and 13,002.12

Step by Step Solution

1. Step 1: Write the proportion equation
   20,502.72 : 30,683.61 = 13,002.12 : x
2. Step 2: Convert to fraction form
   20,502.72/30,683.61 = 13,002.12/x
3. Step 3: Cross multiply
   20,502.72x = 30,683.61 × 13,002.12
4. Step 4: Simplify right side
   20,502.72x = 398,951,979.25
5. Step 5: Solve for x
   x = 398,951,979.25/20,502.72
6. Step 6: Final answer
   x = 19,458.49