Finding the Fourth Proportional to 1,426.91, 1,969.47 and 978.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,426.91 : 1,969.47 = 978.57 : x
2. Step 2: Convert to fraction form
   1,426.91/1,969.47 = 978.57/x
3. Step 3: Cross multiply
   1,426.91x = 1,969.47 × 978.57
4. Step 4: Simplify right side
   1,426.91x = 1,927,264.26
5. Step 5: Solve for x
   x = 1,927,264.26/1,426.91
6. Step 6: Final answer
   x = 1,350.66