Finding the Fourth Proportional to 12,780.67, 19,169.48 and 3,421.42

Step by Step Solution

1. Step 1: Write the proportion equation
   12,780.67 : 19,169.48 = 3,421.42 : x
2. Step 2: Convert to fraction form
   12,780.67/19,169.48 = 3,421.42/x
3. Step 3: Cross multiply
   12,780.67x = 19,169.48 × 3,421.42
4. Step 4: Simplify right side
   12,780.67x = 65,586,802.89
5. Step 5: Solve for x
   x = 65,586,802.89/12,780.67
6. Step 6: Final answer
   x = 5,131.72