Finding the Fourth Proportional to 1,019.74, 1,407.24 and 553.99

Step by Step Solution

1. Step 1: Write the proportion equation
   1,019.74 : 1,407.24 = 553.99 : x
2. Step 2: Convert to fraction form
   1,019.74/1,407.24 = 553.99/x
3. Step 3: Cross multiply
   1,019.74x = 1,407.24 × 553.99
4. Step 4: Simplify right side
   1,019.74x = 779,596.89
5. Step 5: Solve for x
   x = 779,596.89/1,019.74
6. Step 6: Final answer
   x = 764.51