Finding the Fourth Proportional to 1,212.49, 1,819.25 and 519.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,212.49 : 1,819.25 = 519.31 : x
2. Step 2: Convert to fraction form
   1,212.49/1,819.25 = 519.31/x
3. Step 3: Cross multiply
   1,212.49x = 1,819.25 × 519.31
4. Step 4: Simplify right side
   1,212.49x = 944,754.72
5. Step 5: Solve for x
   x = 944,754.72/1,212.49
6. Step 6: Final answer
   x = 779.19