Finding the Fourth Proportional to 1,003.16, 1,503.70 and 386.71

Step by Step Solution

1. Step 1: Write the proportion equation
   1,003.16 : 1,503.70 = 386.71 : x
2. Step 2: Convert to fraction form
   1,003.16/1,503.70 = 386.71/x
3. Step 3: Cross multiply
   1,003.16x = 1,503.70 × 386.71
4. Step 4: Simplify right side
   1,003.16x = 581,495.83
5. Step 5: Solve for x
   x = 581,495.83/1,003.16
6. Step 6: Final answer
   x = 579.66