Finding the Fourth Proportional to 1,641.69, 2,264.57 and 978.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,641.69 : 2,264.57 = 978.50 : x
2. Step 2: Convert to fraction form
   1,641.69/2,264.57 = 978.50/x
3. Step 3: Cross multiply
   1,641.69x = 2,264.57 × 978.50
4. Step 4: Simplify right side
   1,641.69x = 2,215,881.75
5. Step 5: Solve for x
   x = 2,215,881.75/1,641.69
6. Step 6: Final answer
   x = 1,349.76