Finding the Fourth Proportional to 1,420.38, 1,960.20 and 830.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,420.38 : 1,960.20 = 830.88 : x
2. Step 2: Convert to fraction form
   1,420.38/1,960.20 = 830.88/x
3. Step 3: Cross multiply
   1,420.38x = 1,960.20 × 830.88
4. Step 4: Simplify right side
   1,420.38x = 1,628,690.98
5. Step 5: Solve for x
   x = 1,628,690.98/1,420.38
6. Step 6: Final answer
   x = 1,146.66