Finding the Fourth Proportional to 1,538.38, 2,123.02 and 839.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,538.38 : 2,123.02 = 839.78 : x
2. Step 2: Convert to fraction form
   1,538.38/2,123.02 = 839.78/x
3. Step 3: Cross multiply
   1,538.38x = 2,123.02 × 839.78
4. Step 4: Simplify right side
   1,538.38x = 1,782,869.74
5. Step 5: Solve for x
   x = 1,782,869.74/1,538.38
6. Step 6: Final answer
   x = 1,158.93