Finding the Fourth Proportional to 1,128.23, 1,556.72 and 685.36

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.23 : 1,556.72 = 685.36 : x
2. Step 2: Convert to fraction form
   1,128.23/1,556.72 = 685.36/x
3. Step 3: Cross multiply
   1,128.23x = 1,556.72 × 685.36
4. Step 4: Simplify right side
   1,128.23x = 1,066,914.71
5. Step 5: Solve for x
   x = 1,066,914.71/1,128.23
6. Step 6: Final answer
   x = 945.65