Finding the Fourth Proportional to 1,398.75, 2,085.77 and 1,298.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.75 : 2,085.77 = 1,298.31 : x
2. Step 2: Convert to fraction form
   1,398.75/2,085.77 = 1,298.31/x
3. Step 3: Cross multiply
   1,398.75x = 2,085.77 × 1,298.31
4. Step 4: Simplify right side
   1,398.75x = 2,707,969.56
5. Step 5: Solve for x
   x = 2,707,969.56/1,398.75
6. Step 6: Final answer
   x = 1,935.99