Finding the Fourth Proportional to 2,167.90, 2,991.72 and 1,223.73

Step by Step Solution

1. Step 1: Write the proportion equation
   2,167.90 : 2,991.72 = 1,223.73 : x
2. Step 2: Convert to fraction form
   2,167.90/2,991.72 = 1,223.73/x
3. Step 3: Cross multiply
   2,167.90x = 2,991.72 × 1,223.73
4. Step 4: Simplify right side
   2,167.90x = 3,661,051.78
5. Step 5: Solve for x
   x = 3,661,051.78/2,167.90
6. Step 6: Final answer
   x = 1,688.75