Finding the Fourth Proportional to 1,423.78, 1,964.76 and 802.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,423.78 : 1,964.76 = 802.78 : x
2. Step 2: Convert to fraction form
   1,423.78/1,964.76 = 802.78/x
3. Step 3: Cross multiply
   1,423.78x = 1,964.76 × 802.78
4. Step 4: Simplify right side
   1,423.78x = 1,577,270.03
5. Step 5: Solve for x
   x = 1,577,270.03/1,423.78
6. Step 6: Final answer
   x = 1,107.80