Finding the Fourth Proportional to 1,298.35, 1,947.57 and 518.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,298.35 : 1,947.57 = 518.72 : x
2. Step 2: Convert to fraction form
   1,298.35/1,947.57 = 518.72/x
3. Step 3: Cross multiply
   1,298.35x = 1,947.57 × 518.72
4. Step 4: Simplify right side
   1,298.35x = 1,010,243.51
5. Step 5: Solve for x
   x = 1,010,243.51/1,298.35
6. Step 6: Final answer
   x = 778.10