Finding the Fourth Proportional to 1,221.69, 1,685.91 and 662.14

Step by Step Solution

1. Step 1: Write the proportion equation
   1,221.69 : 1,685.91 = 662.14 : x
2. Step 2: Convert to fraction form
   1,221.69/1,685.91 = 662.14/x
3. Step 3: Cross multiply
   1,221.69x = 1,685.91 × 662.14
4. Step 4: Simplify right side
   1,221.69x = 1,116,308.45
5. Step 5: Solve for x
   x = 1,116,308.45/1,221.69
6. Step 6: Final answer
   x = 913.74