Finding the Fourth Proportional to 1,003.15, 1,505.19 and 516.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,003.15 : 1,505.19 = 516.55 : x
2. Step 2: Convert to fraction form
   1,003.15/1,505.19 = 516.55/x
3. Step 3: Cross multiply
   1,003.15x = 1,505.19 × 516.55
4. Step 4: Simplify right side
   1,003.15x = 777,505.89
5. Step 5: Solve for x
   x = 777,505.89/1,003.15
6. Step 6: Final answer
   x = 775.06