Finding the Fourth Proportional to 1,222.32, 1,687.12 and 698.64

Step by Step Solution

1. Step 1: Write the proportion equation
   1,222.32 : 1,687.12 = 698.64 : x
2. Step 2: Convert to fraction form
   1,222.32/1,687.12 = 698.64/x
3. Step 3: Cross multiply
   1,222.32x = 1,687.12 × 698.64
4. Step 4: Simplify right side
   1,222.32x = 1,178,689.52
5. Step 5: Solve for x
   x = 1,178,689.52/1,222.32
6. Step 6: Final answer
   x = 964.31