Finding the Fourth Proportional to 19,488.21, 26,872.56 and 12,405.57

Step by Step Solution

1. Step 1: Write the proportion equation
   19,488.21 : 26,872.56 = 12,405.57 : x
2. Step 2: Convert to fraction form
   19,488.21/26,872.56 = 12,405.57/x
3. Step 3: Cross multiply
   19,488.21x = 26,872.56 × 12,405.57
4. Step 4: Simplify right side
   19,488.21x = 333,369,424.16
5. Step 5: Solve for x
   x = 333,369,424.16/19,488.21
6. Step 6: Final answer
   x = 17,106.21