Finding the Fourth Proportional to 1,431.71, 2,145.90 and 1,172.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,431.71 : 2,145.90 = 1,172.15 : x
2. Step 2: Convert to fraction form
   1,431.71/2,145.90 = 1,172.15/x
3. Step 3: Cross multiply
   1,431.71x = 2,145.90 × 1,172.15
4. Step 4: Simplify right side
   1,431.71x = 2,515,316.69
5. Step 5: Solve for x
   x = 2,515,316.69/1,431.71
6. Step 6: Final answer
   x = 1,756.86