Finding the Fourth Proportional to 20,905.59, 28,863.23 and 12,956.25

Step by Step Solution

1. Step 1: Write the proportion equation
   20,905.59 : 28,863.23 = 12,956.25 : x
2. Step 2: Convert to fraction form
   20,905.59/28,863.23 = 12,956.25/x
3. Step 3: Cross multiply
   20,905.59x = 28,863.23 × 12,956.25
4. Step 4: Simplify right side
   20,905.59x = 373,959,223.69
5. Step 5: Solve for x
   x = 373,959,223.69/20,905.59
6. Step 6: Final answer
   x = 17,888.00