Finding the Fourth Proportional to 1,431.81, 1,976.03 and 872.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,431.81 : 1,976.03 = 872.15 : x
2. Step 2: Convert to fraction form
   1,431.81/1,976.03 = 872.15/x
3. Step 3: Cross multiply
   1,431.81x = 1,976.03 × 872.15
4. Step 4: Simplify right side
   1,431.81x = 1,723,380.32
5. Step 5: Solve for x
   x = 1,723,380.32/1,431.81
6. Step 6: Final answer
   x = 1,203.64