Finding the Fourth Proportional to 1,280.79, 1,919.37 and 510.39

Step by Step Solution

1. Step 1: Write the proportion equation
   1,280.79 : 1,919.37 = 510.39 : x
2. Step 2: Convert to fraction form
   1,280.79/1,919.37 = 510.39/x
3. Step 3: Cross multiply
   1,280.79x = 1,919.37 × 510.39
4. Step 4: Simplify right side
   1,280.79x = 979,627.25
5. Step 5: Solve for x
   x = 979,627.25/1,280.79
6. Step 6: Final answer
   x = 764.86