Finding the Fourth Proportional to 1,005.71, 1,505.33 and 518.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,005.71 : 1,505.33 = 518.09 : x
2. Step 2: Convert to fraction form
   1,005.71/1,505.33 = 518.09/x
3. Step 3: Cross multiply
   1,005.71x = 1,505.33 × 518.09
4. Step 4: Simplify right side
   1,005.71x = 779,899.54
5. Step 5: Solve for x
   x = 779,899.54/1,005.71
6. Step 6: Final answer
   x = 775.47