Finding the Fourth Proportional to 1,222.61, 1,687.68 and 829.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,222.61 : 1,687.68 = 829.86 : x
2. Step 2: Convert to fraction form
   1,222.61/1,687.68 = 829.86/x
3. Step 3: Cross multiply
   1,222.61x = 1,687.68 × 829.86
4. Step 4: Simplify right side
   1,222.61x = 1,400,538.12
5. Step 5: Solve for x
   x = 1,400,538.12/1,222.61
6. Step 6: Final answer
   x = 1,145.54