Finding the Fourth Proportional to 1,189.06, 1,638.36 and 978.52

Step by Step Solution

1. Step 1: Write the proportion equation
   1,189.06 : 1,638.36 = 978.52 : x
2. Step 2: Convert to fraction form
   1,189.06/1,638.36 = 978.52/x
3. Step 3: Cross multiply
   1,189.06x = 1,638.36 × 978.52
4. Step 4: Simplify right side
   1,189.06x = 1,603,168.03
5. Step 5: Solve for x
   x = 1,603,168.03/1,189.06
6. Step 6: Final answer
   x = 1,348.27