Finding the Fourth Proportional to 1,298.98, 1,947.03 and 518.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,298.98 : 1,947.03 = 518.78 : x
2. Step 2: Convert to fraction form
   1,298.98/1,947.03 = 518.78/x
3. Step 3: Cross multiply
   1,298.98x = 1,947.03 × 518.78
4. Step 4: Simplify right side
   1,298.98x = 1,010,080.22
5. Step 5: Solve for x
   x = 1,010,080.22/1,298.98
6. Step 6: Final answer
   x = 777.59