Finding the Fourth Proportional to 1,538.50, 2,123.18 and 839.92

Step by Step Solution

1. Step 1: Write the proportion equation
   1,538.50 : 2,123.18 = 839.92 : x
2. Step 2: Convert to fraction form
   1,538.50/2,123.18 = 839.92/x
3. Step 3: Cross multiply
   1,538.50x = 2,123.18 × 839.92
4. Step 4: Simplify right side
   1,538.50x = 1,783,301.35
5. Step 5: Solve for x
   x = 1,783,301.35/1,538.50
6. Step 6: Final answer
   x = 1,159.12