Finding the Fourth Proportional to 1,420.27, 1,959.34 and 830.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,420.27 : 1,959.34 = 830.55 : x
2. Step 2: Convert to fraction form
   1,420.27/1,959.34 = 830.55/x
3. Step 3: Cross multiply
   1,420.27x = 1,959.34 × 830.55
4. Step 4: Simplify right side
   1,420.27x = 1,627,320.04
5. Step 5: Solve for x
   x = 1,627,320.04/1,420.27
6. Step 6: Final answer
   x = 1,145.78