Finding the Fourth Proportional to 1,420.34, 1,959.90 and 830.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,420.34 : 1,959.90 = 830.80 : x
2. Step 2: Convert to fraction form
   1,420.34/1,959.90 = 830.80/x
3. Step 3: Cross multiply
   1,420.34x = 1,959.90 × 830.80
4. Step 4: Simplify right side
   1,420.34x = 1,628,284.92
5. Step 5: Solve for x
   x = 1,628,284.92/1,420.34
6. Step 6: Final answer
   x = 1,146.41