Finding the Fourth Proportional to 1,081.80, 1,620.27 and 648.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.80 : 1,620.27 = 648.05 : x
2. Step 2: Convert to fraction form
   1,081.80/1,620.27 = 648.05/x
3. Step 3: Cross multiply
   1,081.80x = 1,620.27 × 648.05
4. Step 4: Simplify right side
   1,081.80x = 1,050,015.97
5. Step 5: Solve for x
   x = 1,050,015.97/1,081.80
6. Step 6: Final answer
   x = 970.62