Finding the Fourth Proportional to 1,408.80, 1,943.50 and 911.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,408.80 : 1,943.50 = 911.61 : x
2. Step 2: Convert to fraction form
   1,408.80/1,943.50 = 911.61/x
3. Step 3: Cross multiply
   1,408.80x = 1,943.50 × 911.61
4. Step 4: Simplify right side
   1,408.80x = 1,771,704.32
5. Step 5: Solve for x
   x = 1,771,704.32/1,408.80
6. Step 6: Final answer
   x = 1,257.60