Finding the Fourth Proportional to 1,279.33, 1,921.59 and 987.39

Step by Step Solution

1. Step 1: Write the proportion equation
   1,279.33 : 1,921.59 = 987.39 : x
2. Step 2: Convert to fraction form
   1,279.33/1,921.59 = 987.39/x
3. Step 3: Cross multiply
   1,279.33x = 1,921.59 × 987.39
4. Step 4: Simplify right side
   1,279.33x = 1,897,358.75
5. Step 5: Solve for x
   x = 1,897,358.75/1,279.33
6. Step 6: Final answer
   x = 1,483.09