Finding the Fourth Proportional to 1,420.10, 1,959.89 and 830.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,420.10 : 1,959.89 = 830.60 : x
2. Step 2: Convert to fraction form
   1,420.10/1,959.89 = 830.60/x
3. Step 3: Cross multiply
   1,420.10x = 1,959.89 × 830.60
4. Step 4: Simplify right side
   1,420.10x = 1,627,884.63
5. Step 5: Solve for x
   x = 1,627,884.63/1,420.10
6. Step 6: Final answer
   x = 1,146.32