Finding the Fourth Proportional to 1,440.69, 2,157.61 and 891.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,440.69 : 2,157.61 = 891.20 : x
2. Step 2: Convert to fraction form
   1,440.69/2,157.61 = 891.20/x
3. Step 3: Cross multiply
   1,440.69x = 2,157.61 × 891.20
4. Step 4: Simplify right side
   1,440.69x = 1,922,869.38
5. Step 5: Solve for x
   x = 1,922,869.38/1,440.69
6. Step 6: Final answer
   x = 1,334.69