Finding the Fourth Proportional to 21,783.60, 32,680.02 and 12,428.10

Step by Step Solution

1. Step 1: Write the proportion equation
   21,783.60 : 32,680.02 = 12,428.10 : x
2. Step 2: Convert to fraction form
   21,783.60/32,680.02 = 12,428.10/x
3. Step 3: Cross multiply
   21,783.60x = 32,680.02 × 12,428.10
4. Step 4: Simplify right side
   21,783.60x = 406,150,556.56
5. Step 5: Solve for x
   x = 406,150,556.56/21,783.60
6. Step 6: Final answer
   x = 18,644.79