Finding the Fourth Proportional to 1,642.86, 2,266.79 and 978.53

Step by Step Solution

1. Step 1: Write the proportion equation
   1,642.86 : 2,266.79 = 978.53 : x
2. Step 2: Convert to fraction form
   1,642.86/2,266.79 = 978.53/x
3. Step 3: Cross multiply
   1,642.86x = 2,266.79 × 978.53
4. Step 4: Simplify right side
   1,642.86x = 2,218,105.79
5. Step 5: Solve for x
   x = 2,218,105.79/1,642.86
6. Step 6: Final answer
   x = 1,350.15