Finding the Fourth Proportional to 1,311.64, 1,965.52 and 661.48

Step by Step Solution

1. Step 1: Write the proportion equation
   1,311.64 : 1,965.52 = 661.48 : x
2. Step 2: Convert to fraction form
   1,311.64/1,965.52 = 661.48/x
3. Step 3: Cross multiply
   1,311.64x = 1,965.52 × 661.48
4. Step 4: Simplify right side
   1,311.64x = 1,300,152.17
5. Step 5: Solve for x
   x = 1,300,152.17/1,311.64
6. Step 6: Final answer
   x = 991.24