Finding the Fourth Proportional to 1,431.72, 1,975.72 and 810.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,431.72 : 1,975.72 = 810.72 : x
2. Step 2: Convert to fraction form
   1,431.72/1,975.72 = 810.72/x
3. Step 3: Cross multiply
   1,431.72x = 1,975.72 × 810.72
4. Step 4: Simplify right side
   1,431.72x = 1,601,755.72
5. Step 5: Solve for x
   x = 1,601,755.72/1,431.72
6. Step 6: Final answer
   x = 1,118.76