Finding the Fourth Proportional to 1,707.45, 2,355.48 and 999.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,707.45 : 2,355.48 = 999.31 : x
2. Step 2: Convert to fraction form
   1,707.45/2,355.48 = 999.31/x
3. Step 3: Cross multiply
   1,707.45x = 2,355.48 × 999.31
4. Step 4: Simplify right side
   1,707.45x = 2,353,854.72
5. Step 5: Solve for x
   x = 2,353,854.72/1,707.45
6. Step 6: Final answer
   x = 1,378.58