Finding the Fourth Proportional to 1,271.84, 1,755.98 and 978.64

Step by Step Solution

1. Step 1: Write the proportion equation
   1,271.84 : 1,755.98 = 978.64 : x
2. Step 2: Convert to fraction form
   1,271.84/1,755.98 = 978.64/x
3. Step 3: Cross multiply
   1,271.84x = 1,755.98 × 978.64
4. Step 4: Simplify right side
   1,271.84x = 1,718,472.27
5. Step 5: Solve for x
   x = 1,718,472.27/1,271.84
6. Step 6: Final answer
   x = 1,351.17