Finding the Fourth Proportional to 1,317.72, 1,973.34 and 831.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,317.72 : 1,973.34 = 831.72 : x
2. Step 2: Convert to fraction form
   1,317.72/1,973.34 = 831.72/x
3. Step 3: Cross multiply
   1,317.72x = 1,973.34 × 831.72
4. Step 4: Simplify right side
   1,317.72x = 1,641,266.34
5. Step 5: Solve for x
   x = 1,641,266.34/1,317.72
6. Step 6: Final answer
   x = 1,245.53