Finding the Fourth Proportional to 1,077.30, 1,616.00 and 643.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,077.30 : 1,616.00 = 643.50 : x
2. Step 2: Convert to fraction form
   1,077.30/1,616.00 = 643.50/x
3. Step 3: Cross multiply
   1,077.30x = 1,616.00 × 643.50
4. Step 4: Simplify right side
   1,077.30x = 1,039,892.78
5. Step 5: Solve for x
   x = 1,039,892.78/1,077.30
6. Step 6: Final answer
   x = 965.28