Finding the Fourth Proportional to 1,538.55, 2,123.16 and 839.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,538.55 : 2,123.16 = 839.91 : x
2. Step 2: Convert to fraction form
   1,538.55/2,123.16 = 839.91/x
3. Step 3: Cross multiply
   1,538.55x = 2,123.16 × 839.91
4. Step 4: Simplify right side
   1,538.55x = 1,783,263.32
5. Step 5: Solve for x
   x = 1,783,263.32/1,538.55
6. Step 6: Final answer
   x = 1,159.05