Finding the Fourth Proportional to 20,384.50, 28,133.69 and 12,431.34

Step by Step Solution

1. Step 1: Write the proportion equation
   20,384.50 : 28,133.69 = 12,431.34 : x
2. Step 2: Convert to fraction form
   20,384.50/28,133.69 = 12,431.34/x
3. Step 3: Cross multiply
   20,384.50x = 28,133.69 × 12,431.34
4. Step 4: Simplify right side
   20,384.50x = 349,739,263.02
5. Step 5: Solve for x
   x = 349,739,263.02/20,384.50
6. Step 6: Final answer
   x = 17,157.12