Finding the Fourth Proportional to 1,189.88, 1,641.98 and 665.82

Step by Step Solution

1. Step 1: Write the proportion equation
   1,189.88 : 1,641.98 = 665.82 : x
2. Step 2: Convert to fraction form
   1,189.88/1,641.98 = 665.82/x
3. Step 3: Cross multiply
   1,189.88x = 1,641.98 × 665.82
4. Step 4: Simplify right side
   1,189.88x = 1,093,263.12
5. Step 5: Solve for x
   x = 1,093,263.12/1,189.88
6. Step 6: Final answer
   x = 918.80