Finding the Fourth Proportional to 1,643.91, 2,268.89 and 980.81

Step by Step Solution

1. Step 1: Write the proportion equation
   1,643.91 : 2,268.89 = 980.81 : x
2. Step 2: Convert to fraction form
   1,643.91/2,268.89 = 980.81/x
3. Step 3: Cross multiply
   1,643.91x = 2,268.89 × 980.81
4. Step 4: Simplify right side
   1,643.91x = 2,225,333.75
5. Step 5: Solve for x
   x = 2,225,333.75/1,643.91
6. Step 6: Final answer
   x = 1,353.68