Finding the Fourth Proportional to 1,436.31, 1,980.69 and 869.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,436.31 : 1,980.69 = 869.12 : x
2. Step 2: Convert to fraction form
   1,436.31/1,980.69 = 869.12/x
3. Step 3: Cross multiply
   1,436.31x = 1,980.69 × 869.12
4. Step 4: Simplify right side
   1,436.31x = 1,721,447.39
5. Step 5: Solve for x
   x = 1,721,447.39/1,436.31
6. Step 6: Final answer
   x = 1,198.52