Finding the Fourth Proportional to 20,613.34, 28,436.24 and 13,890.34

Step by Step Solution

1. Step 1: Write the proportion equation
   20,613.34 : 28,436.24 = 13,890.34 : x
2. Step 2: Convert to fraction form
   20,613.34/28,436.24 = 13,890.34/x
3. Step 3: Cross multiply
   20,613.34x = 28,436.24 × 13,890.34
4. Step 4: Simplify right side
   20,613.34x = 394,989,041.92
5. Step 5: Solve for x
   x = 394,989,041.92/20,613.34
6. Step 6: Final answer
   x = 19,161.82