Finding the Fourth Proportional to 2,148.80, 3,219.93 and 978.12

Step by Step Solution

1. Step 1: Write the proportion equation
   2,148.80 : 3,219.93 = 978.12 : x
2. Step 2: Convert to fraction form
   2,148.80/3,219.93 = 978.12/x
3. Step 3: Cross multiply
   2,148.80x = 3,219.93 × 978.12
4. Step 4: Simplify right side
   2,148.80x = 3,149,477.93
5. Step 5: Solve for x
   x = 3,149,477.93/2,148.80
6. Step 6: Final answer
   x = 1,465.69