Finding the Fourth Proportional to 1,421.15, 1,960.67 and 800.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,421.15 : 1,960.67 = 800.15 : x
2. Step 2: Convert to fraction form
   1,421.15/1,960.67 = 800.15/x
3. Step 3: Cross multiply
   1,421.15x = 1,960.67 × 800.15
4. Step 4: Simplify right side
   1,421.15x = 1,568,822.30
5. Step 5: Solve for x
   x = 1,568,822.30/1,421.15
6. Step 6: Final answer
   x = 1,103.91