Finding the Fourth Proportional to 20,522.50, 28,328.34 and 12,139

Step by Step Solution

1. Step 1: Write the proportion equation
   20,522.50 : 28,328.34 = 12,139 : x
2. Step 2: Convert to fraction form
   20,522.50/28,328.34 = 12,139/x
3. Step 3: Cross multiply
   20,522.50x = 28,328.34 × 12,139
4. Step 4: Simplify right side
   20,522.50x = 343,877,719.26
5. Step 5: Solve for x
   x = 343,877,719.26/20,522.50
6. Step 6: Final answer
   x = 16,756.13