Finding the Fourth Proportional to 1,421.40, 1,960.83 and 1,224.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,421.40 : 1,960.83 = 1,224.57 : x
2. Step 2: Convert to fraction form
   1,421.40/1,960.83 = 1,224.57/x
3. Step 3: Cross multiply
   1,421.40x = 1,960.83 × 1,224.57
4. Step 4: Simplify right side
   1,421.40x = 2,401,173.59
5. Step 5: Solve for x
   x = 2,401,173.59/1,421.40
6. Step 6: Final answer
   x = 1,689.30