Finding the Fourth Proportional to 1,640.94, 2,264.49 and 978.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,640.94 : 2,264.49 = 978.10 : x
2. Step 2: Convert to fraction form
   1,640.94/2,264.49 = 978.10/x
3. Step 3: Cross multiply
   1,640.94x = 2,264.49 × 978.10
4. Step 4: Simplify right side
   1,640.94x = 2,214,897.67
5. Step 5: Solve for x
   x = 2,214,897.67/1,640.94
6. Step 6: Final answer
   x = 1,349.77