Finding the Fourth Proportional to 1,019.78, 1,407.30 and 554.03

Step by Step Solution

1. Step 1: Write the proportion equation
   1,019.78 : 1,407.30 = 554.03 : x
2. Step 2: Convert to fraction form
   1,019.78/1,407.30 = 554.03/x
3. Step 3: Cross multiply
   1,019.78x = 1,407.30 × 554.03
4. Step 4: Simplify right side
   1,019.78x = 779,687.49
5. Step 5: Solve for x
   x = 779,687.49/1,019.78
6. Step 6: Final answer
   x = 764.56