Finding the Fourth Proportional to 12,838.16, 17,714.90 and 7,172.20

Step by Step Solution

1. Step 1: Write the proportion equation
   12,838.16 : 17,714.90 = 7,172.20 : x
2. Step 2: Convert to fraction form
   12,838.16/17,714.90 = 7,172.20/x
3. Step 3: Cross multiply
   12,838.16x = 17,714.90 × 7,172.20
4. Step 4: Simplify right side
   12,838.16x = 127,054,855.33
5. Step 5: Solve for x
   x = 127,054,855.33/12,838.16
6. Step 6: Final answer
   x = 9,896.66