Finding the Fourth Proportional to 1,290.56, 1,935.81 and 316.67

Step by Step Solution

1. Step 1: Write the proportion equation
   1,290.56 : 1,935.81 = 316.67 : x
2. Step 2: Convert to fraction form
   1,290.56/1,935.81 = 316.67/x
3. Step 3: Cross multiply
   1,290.56x = 1,935.81 × 316.67
4. Step 4: Simplify right side
   1,290.56x = 613,003.27
5. Step 5: Solve for x
   x = 613,003.27/1,290.56
6. Step 6: Final answer
   x = 474.99