Finding the Fourth Proportional to 2,145.53, 3,215.39 and 911.40

Step by Step Solution

1. Step 1: Write the proportion equation
   2,145.53 : 3,215.39 = 911.40 : x
2. Step 2: Convert to fraction form
   2,145.53/3,215.39 = 911.40/x
3. Step 3: Cross multiply
   2,145.53x = 3,215.39 × 911.40
4. Step 4: Simplify right side
   2,145.53x = 2,930,485.81
5. Step 5: Solve for x
   x = 2,930,485.81/2,145.53
6. Step 6: Final answer
   x = 1,365.86