Finding the Fourth Proportional to 1,238.31, 1,859.31 and 509.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,238.31 : 1,859.31 = 509.31 : x
2. Step 2: Convert to fraction form
   1,238.31/1,859.31 = 509.31/x
3. Step 3: Cross multiply
   1,238.31x = 1,859.31 × 509.31
4. Step 4: Simplify right side
   1,238.31x = 946,965.18
5. Step 5: Solve for x
   x = 946,965.18/1,238.31
6. Step 6: Final answer
   x = 764.72