Finding the Fourth Proportional to 1,222.59, 1,687.18 and 698.63

Step by Step Solution

1. Step 1: Write the proportion equation
   1,222.59 : 1,687.18 = 698.63 : x
2. Step 2: Convert to fraction form
   1,222.59/1,687.18 = 698.63/x
3. Step 3: Cross multiply
   1,222.59x = 1,687.18 × 698.63
4. Step 4: Simplify right side
   1,222.59x = 1,178,705.69
5. Step 5: Solve for x
   x = 1,178,705.69/1,222.59
6. Step 6: Final answer
   x = 964.10