Finding the Fourth Proportional to 1,019.90, 1,407.34 and 571.71

Step by Step Solution

1. Step 1: Write the proportion equation
   1,019.90 : 1,407.34 = 571.71 : x
2. Step 2: Convert to fraction form
   1,019.90/1,407.34 = 571.71/x
3. Step 3: Cross multiply
   1,019.90x = 1,407.34 × 571.71
4. Step 4: Simplify right side
   1,019.90x = 804,583.31
5. Step 5: Solve for x
   x = 804,583.31/1,019.90
6. Step 6: Final answer
   x = 788.89