Finding the Fourth Proportional to 1,980.20, 2,965.17 and 1,328.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,980.20 : 2,965.17 = 1,328.96 : x
2. Step 2: Convert to fraction form
   1,980.20/2,965.17 = 1,328.96/x
3. Step 3: Cross multiply
   1,980.20x = 2,965.17 × 1,328.96
4. Step 4: Simplify right side
   1,980.20x = 3,940,592.32
5. Step 5: Solve for x
   x = 3,940,592.32/1,980.20
6. Step 6: Final answer
   x = 1,990.00