Finding the Fourth Proportional to 1,019.40, 1,406.80 and 577.28

Step by Step Solution

1. Step 1: Write the proportion equation
   1,019.40 : 1,406.80 = 577.28 : x
2. Step 2: Convert to fraction form
   1,019.40/1,406.80 = 577.28/x
3. Step 3: Cross multiply
   1,019.40x = 1,406.80 × 577.28
4. Step 4: Simplify right side
   1,019.40x = 812,117.50
5. Step 5: Solve for x
   x = 812,117.50/1,019.40
6. Step 6: Final answer
   x = 796.66