Finding the Fourth Proportional to 1,317.89, 1,976.18 and 393.34

Step by Step Solution

1. Step 1: Write the proportion equation
   1,317.89 : 1,976.18 = 393.34 : x
2. Step 2: Convert to fraction form
   1,317.89/1,976.18 = 393.34/x
3. Step 3: Cross multiply
   1,317.89x = 1,976.18 × 393.34
4. Step 4: Simplify right side
   1,317.89x = 777,310.64
5. Step 5: Solve for x
   x = 777,310.64/1,317.89
6. Step 6: Final answer
   x = 589.81