Finding the Fourth Proportional to 1,188.59, 1,642.55 and 978.48

Step by Step Solution

1. Step 1: Write the proportion equation
   1,188.59 : 1,642.55 = 978.48 : x
2. Step 2: Convert to fraction form
   1,188.59/1,642.55 = 978.48/x
3. Step 3: Cross multiply
   1,188.59x = 1,642.55 × 978.48
4. Step 4: Simplify right side
   1,188.59x = 1,607,197.43
5. Step 5: Solve for x
   x = 1,607,197.43/1,188.59
6. Step 6: Final answer
   x = 1,352.19