Finding the Fourth Proportional to 1,643.69, 2,267.93 and 980.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,643.69 : 2,267.93 = 980.78 : x
2. Step 2: Convert to fraction form
   1,643.69/2,267.93 = 980.78/x
3. Step 3: Cross multiply
   1,643.69x = 2,267.93 × 980.78
4. Step 4: Simplify right side
   1,643.69x = 2,224,331.50
5. Step 5: Solve for x
   x = 2,224,331.50/1,643.69
6. Step 6: Final answer
   x = 1,353.25