Finding the Fourth Proportional to 20,788.56, 31,106.40 and 19,662.72

Step by Step Solution

1. Step 1: Write the proportion equation
   20,788.56 : 31,106.40 = 19,662.72 : x
2. Step 2: Convert to fraction form
   20,788.56/31,106.40 = 19,662.72/x
3. Step 3: Cross multiply
   20,788.56x = 31,106.40 × 19,662.72
4. Step 4: Simplify right side
   20,788.56x = 611,636,433.41
5. Step 5: Solve for x
   x = 611,636,433.41/20,788.56
6. Step 6: Final answer
   x = 29,421.78