Finding the Fourth Proportional to 1,077.52, 1,616.34 and 428.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,077.52 : 1,616.34 = 428.72 : x
2. Step 2: Convert to fraction form
   1,077.52/1,616.34 = 428.72/x
3. Step 3: Cross multiply
   1,077.52x = 1,616.34 × 428.72
4. Step 4: Simplify right side
   1,077.52x = 692,957.28
5. Step 5: Solve for x
   x = 692,957.28/1,077.52
6. Step 6: Final answer
   x = 643.10