Finding the Fourth Proportional to 1,431.56, 1,976.40 and 900.56

Step by Step Solution

1. Step 1: Write the proportion equation
   1,431.56 : 1,976.40 = 900.56 : x
2. Step 2: Convert to fraction form
   1,431.56/1,976.40 = 900.56/x
3. Step 3: Cross multiply
   1,431.56x = 1,976.40 × 900.56
4. Step 4: Simplify right side
   1,431.56x = 1,779,866.78
5. Step 5: Solve for x
   x = 1,779,866.78/1,431.56
6. Step 6: Final answer
   x = 1,243.31