Finding the Fourth Proportional to 1,066.56, 1,472.16 and 717.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,066.56 : 1,472.16 = 717.20 : x
2. Step 2: Convert to fraction form
   1,066.56/1,472.16 = 717.20/x
3. Step 3: Cross multiply
   1,066.56x = 1,472.16 × 717.20
4. Step 4: Simplify right side
   1,066.56x = 1,055,833.15
5. Step 5: Solve for x
   x = 1,055,833.15/1,066.56
6. Step 6: Final answer
   x = 989.94