Finding the Fourth Proportional to 1,290.72, 1,936.05 and 316.83

Step by Step Solution

1. Step 1: Write the proportion equation
   1,290.72 : 1,936.05 = 316.83 : x
2. Step 2: Convert to fraction form
   1,290.72/1,936.05 = 316.83/x
3. Step 3: Cross multiply
   1,290.72x = 1,936.05 × 316.83
4. Step 4: Simplify right side
   1,290.72x = 613,398.72
5. Step 5: Solve for x
   x = 613,398.72/1,290.72
6. Step 6: Final answer
   x = 475.24