Finding the Fourth Proportional to 1,291.35, 1,936.31 and 510.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,291.35 : 1,936.31 = 510.56 : x
2. Step 2: Convert to fraction form
   1,291.35/1,936.31 = 510.56/x
3. Step 3: Cross multiply
   1,291.35x = 1,936.31 × 510.56
4. Step 4: Simplify right side
   1,291.35x = 988,608.55
5. Step 5: Solve for x
   x = 988,608.55/1,291.35
6. Step 6: Final answer
   x = 765.56