Finding the Fourth Proportional to 1,383.90, 1,909.65 and 824.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,383.90 : 1,909.65 = 824.55 : x
2. Step 2: Convert to fraction form
   1,383.90/1,909.65 = 824.55/x
3. Step 3: Cross multiply
   1,383.90x = 1,909.65 × 824.55
4. Step 4: Simplify right side
   1,383.90x = 1,574,601.91
5. Step 5: Solve for x
   x = 1,574,601.91/1,383.90
6. Step 6: Final answer
   x = 1,137.80