Finding the Fourth Proportional to 1,311.12, 1,965.60 and 661.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,311.12 : 1,965.60 = 661.52 : x
2. Step 2: Convert to fraction form
   1,311.12/1,965.60 = 661.52/x
3. Step 3: Cross multiply
   1,311.12x = 1,965.60 × 661.52
4. Step 4: Simplify right side
   1,311.12x = 1,300,283.71
5. Step 5: Solve for x
   x = 1,300,283.71/1,311.12
6. Step 6: Final answer
   x = 991.74