Finding the Fourth Proportional to 1,978.38, 2,966.57 and 661.67

Step by Step Solution

1. Step 1: Write the proportion equation
   1,978.38 : 2,966.57 = 661.67 : x
2. Step 2: Convert to fraction form
   1,978.38/2,966.57 = 661.67/x
3. Step 3: Cross multiply
   1,978.38x = 2,966.57 × 661.67
4. Step 4: Simplify right side
   1,978.38x = 1,962,906.25
5. Step 5: Solve for x
   x = 1,962,906.25/1,978.38
6. Step 6: Final answer
   x = 992.18