Finding the Fourth Proportional to 1,641.21, 2,264.86 and 978.06

Step by Step Solution

1. Step 1: Write the proportion equation
   1,641.21 : 2,264.86 = 978.06 : x
2. Step 2: Convert to fraction form
   1,641.21/2,264.86 = 978.06/x
3. Step 3: Cross multiply
   1,641.21x = 2,264.86 × 978.06
4. Step 4: Simplify right side
   1,641.21x = 2,215,168.97
5. Step 5: Solve for x
   x = 2,215,168.97/1,641.21
6. Step 6: Final answer
   x = 1,349.72