Finding the Fourth Proportional to 2,167.50, 2,990.81 and 1,223.21

Step by Step Solution

1. Step 1: Write the proportion equation
   2,167.50 : 2,990.81 = 1,223.21 : x
2. Step 2: Convert to fraction form
   2,167.50/2,990.81 = 1,223.21/x
3. Step 3: Cross multiply
   2,167.50x = 2,990.81 × 1,223.21
4. Step 4: Simplify right side
   2,167.50x = 3,658,388.70
5. Step 5: Solve for x
   x = 3,658,388.70/2,167.50
6. Step 6: Final answer
   x = 1,687.84