Finding the Fourth Proportional to 1,665.78, 2,499.78 and 936

Step by Step Solution

1. Step 1: Write the proportion equation
   1,665.78 : 2,499.78 = 936 : x
2. Step 2: Convert to fraction form
   1,665.78/2,499.78 = 936/x
3. Step 3: Cross multiply
   1,665.78x = 2,499.78 × 936
4. Step 4: Simplify right side
   1,665.78x = 2,339,794.08
5. Step 5: Solve for x
   x = 2,339,794.08/1,665.78
6. Step 6: Final answer
   x = 1,404.62