Finding the Fourth Proportional to 1,189.50, 1,641.55 and 665.53

Step by Step Solution

1. Step 1: Write the proportion equation
   1,189.50 : 1,641.55 = 665.53 : x
2. Step 2: Convert to fraction form
   1,189.50/1,641.55 = 665.53/x
3. Step 3: Cross multiply
   1,189.50x = 1,641.55 × 665.53
4. Step 4: Simplify right side
   1,189.50x = 1,092,499.11
5. Step 5: Solve for x
   x = 1,092,499.11/1,189.50
6. Step 6: Final answer
   x = 918.46