Finding the Fourth Proportional to 12,912.30, 18,116.10 and 12,912.30

Step by Step Solution

1. Step 1: Write the proportion equation
   12,912.30 : 18,116.10 = 12,912.30 : x
2. Step 2: Convert to fraction form
   12,912.30/18,116.10 = 12,912.30/x
3. Step 3: Cross multiply
   12,912.30x = 18,116.10 × 12,912.30
4. Step 4: Simplify right side
   12,912.30x = 233,920,518.03
5. Step 5: Solve for x
   x = 233,920,518.03/12,912.30
6. Step 6: Final answer
   x = 18,116.10