Finding the Fourth Proportional to 1,431.57, 1,976.05 and 872.07

Step by Step Solution

1. Step 1: Write the proportion equation
   1,431.57 : 1,976.05 = 872.07 : x
2. Step 2: Convert to fraction form
   1,431.57/1,976.05 = 872.07/x
3. Step 3: Cross multiply
   1,431.57x = 1,976.05 × 872.07
4. Step 4: Simplify right side
   1,431.57x = 1,723,242.70
5. Step 5: Solve for x
   x = 1,723,242.70/1,431.57
6. Step 6: Final answer
   x = 1,203.74