Finding the Fourth Proportional to 20,815.99, 28,727.83 and 12,749.60

Step by Step Solution

1. Step 1: Write the proportion equation
   20,815.99 : 28,727.83 = 12,749.60 : x
2. Step 2: Convert to fraction form
   20,815.99/28,727.83 = 12,749.60/x
3. Step 3: Cross multiply
   20,815.99x = 28,727.83 × 12,749.60
4. Step 4: Simplify right side
   20,815.99x = 366,268,429.12
5. Step 5: Solve for x
   x = 366,268,429.12/20,815.99
6. Step 6: Final answer
   x = 17,595.53