Finding the Fourth Proportional to 2,091.80, 3,138.17 and 980.39

Step by Step Solution

1. Step 1: Write the proportion equation
   2,091.80 : 3,138.17 = 980.39 : x
2. Step 2: Convert to fraction form
   2,091.80/3,138.17 = 980.39/x
3. Step 3: Cross multiply
   2,091.80x = 3,138.17 × 980.39
4. Step 4: Simplify right side
   2,091.80x = 3,076,633.43
5. Step 5: Solve for x
   x = 3,076,633.43/2,091.80
6. Step 6: Final answer
   x = 1,470.80