Finding the Fourth Proportional to 2,645.33, 3,966.74 and 978.90

Step by Step Solution

1. Step 1: Write the proportion equation
   2,645.33 : 3,966.74 = 978.90 : x
2. Step 2: Convert to fraction form
   2,645.33/3,966.74 = 978.90/x
3. Step 3: Cross multiply
   2,645.33x = 3,966.74 × 978.90
4. Step 4: Simplify right side
   2,645.33x = 3,883,036.89
5. Step 5: Solve for x
   x = 3,883,036.89/2,645.33
6. Step 6: Final answer
   x = 1,467.89