Finding the Fourth Proportional to 1,221.83, 1,686.12 and 662.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,221.83 : 1,686.12 = 662.30 : x
2. Step 2: Convert to fraction form
   1,221.83/1,686.12 = 662.30/x
3. Step 3: Cross multiply
   1,221.83x = 1,686.12 × 662.30
4. Step 4: Simplify right side
   1,221.83x = 1,116,725.89
5. Step 5: Solve for x
   x = 1,116,725.89/1,221.83
6. Step 6: Final answer
   x = 913.97