Finding the Fourth Proportional to 1,223.79, 1,689.67 and 826.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,223.79 : 1,689.67 = 826.05 : x
2. Step 2: Convert to fraction form
   1,223.79/1,689.67 = 826.05/x
3. Step 3: Cross multiply
   1,223.79x = 1,689.67 × 826.05
4. Step 4: Simplify right side
   1,223.79x = 1,395,751.90
5. Step 5: Solve for x
   x = 1,395,751.90/1,223.79
6. Step 6: Final answer
   x = 1,140.52