Finding the Fourth Proportional to 1,189.05, 1,640.89 and 665.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,189.05 : 1,640.89 = 665.09 : x
2. Step 2: Convert to fraction form
   1,189.05/1,640.89 = 665.09/x
3. Step 3: Cross multiply
   1,189.05x = 1,640.89 × 665.09
4. Step 4: Simplify right side
   1,189.05x = 1,091,328.00
5. Step 5: Solve for x
   x = 1,091,328.00/1,189.05
6. Step 6: Final answer
   x = 917.82