Finding the Fourth Proportional to 1,509.48, 2,081.76 and 978.40

Step by Step Solution

1. Step 1: Write the proportion equation
   1,509.48 : 2,081.76 = 978.40 : x
2. Step 2: Convert to fraction form
   1,509.48/2,081.76 = 978.40/x
3. Step 3: Cross multiply
   1,509.48x = 2,081.76 × 978.40
4. Step 4: Simplify right side
   1,509.48x = 2,036,793.98
5. Step 5: Solve for x
   x = 2,036,793.98/1,509.48
6. Step 6: Final answer
   x = 1,349.33