Finding the Fourth Proportional to 20,938.10, 28,895.94 and 12,985.62

Step by Step Solution

1. Step 1: Write the proportion equation
   20,938.10 : 28,895.94 = 12,985.62 : x
2. Step 2: Convert to fraction form
   20,938.10/28,895.94 = 12,985.62/x
3. Step 3: Cross multiply
   20,938.10x = 28,895.94 × 12,985.62
4. Step 4: Simplify right side
   20,938.10x = 375,231,486.98
5. Step 5: Solve for x
   x = 375,231,486.98/20,938.10
6. Step 6: Final answer
   x = 17,920.99