Finding the Fourth Proportional to 1,428.72, 2,140.86 and 964.68

Step by Step Solution

1. Step 1: Write the proportion equation
   1,428.72 : 2,140.86 = 964.68 : x
2. Step 2: Convert to fraction form
   1,428.72/2,140.86 = 964.68/x
3. Step 3: Cross multiply
   1,428.72x = 2,140.86 × 964.68
4. Step 4: Simplify right side
   1,428.72x = 2,065,244.82
5. Step 5: Solve for x
   x = 2,065,244.82/1,428.72
6. Step 6: Final answer
   x = 1,445.52