Finding the Fourth Proportional to 1,019.71, 1,407.18 and 553.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,019.71 : 1,407.18 = 553.96 : x
2. Step 2: Convert to fraction form
   1,019.71/1,407.18 = 553.96/x
3. Step 3: Cross multiply
   1,019.71x = 1,407.18 × 553.96
4. Step 4: Simplify right side
   1,019.71x = 779,521.43
5. Step 5: Solve for x
   x = 779,521.43/1,019.71
6. Step 6: Final answer
   x = 764.45