Finding the Fourth Proportional to 1,431.12, 2,142.90 and 1,236.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,431.12 : 2,142.90 = 1,236.72 : x
2. Step 2: Convert to fraction form
   1,431.12/2,142.90 = 1,236.72/x
3. Step 3: Cross multiply
   1,431.12x = 2,142.90 × 1,236.72
4. Step 4: Simplify right side
   1,431.12x = 2,650,167.29
5. Step 5: Solve for x
   x = 2,650,167.29/1,431.12
6. Step 6: Final answer
   x = 1,851.81