Finding the Fourth Proportional to 1,298.31, 1,791.69 and 708.87

Step by Step Solution

1. Step 1: Write the proportion equation
   1,298.31 : 1,791.69 = 708.87 : x
2. Step 2: Convert to fraction form
   1,298.31/1,791.69 = 708.87/x
3. Step 3: Cross multiply
   1,298.31x = 1,791.69 × 708.87
4. Step 4: Simplify right side
   1,298.31x = 1,270,075.29
5. Step 5: Solve for x
   x = 1,270,075.29/1,298.31
6. Step 6: Final answer
   x = 978.25