Finding the Fourth Proportional to 1,388.30, 2,077.24 and 830.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.30 : 2,077.24 = 830.96 : x
2. Step 2: Convert to fraction form
   1,388.30/2,077.24 = 830.96/x
3. Step 3: Cross multiply
   1,388.30x = 2,077.24 × 830.96
4. Step 4: Simplify right side
   1,388.30x = 1,726,099.20
5. Step 5: Solve for x
   x = 1,726,099.20/1,388.30
6. Step 6: Final answer
   x = 1,243.32