Finding the Fourth Proportional to 1,003.19, 1,505.03 and 386.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,003.19 : 1,505.03 = 386.72 : x
2. Step 2: Convert to fraction form
   1,003.19/1,505.03 = 386.72/x
3. Step 3: Cross multiply
   1,003.19x = 1,505.03 × 386.72
4. Step 4: Simplify right side
   1,003.19x = 582,025.20
5. Step 5: Solve for x
   x = 582,025.20/1,003.19
6. Step 6: Final answer
   x = 580.18