Finding the Fourth Proportional to 1,030.50, 1,542.72 and 639.32

Step by Step Solution

1. Step 1: Write the proportion equation
   1,030.50 : 1,542.72 = 639.32 : x
2. Step 2: Convert to fraction form
   1,030.50/1,542.72 = 639.32/x
3. Step 3: Cross multiply
   1,030.50x = 1,542.72 × 639.32
4. Step 4: Simplify right side
   1,030.50x = 986,284.04
5. Step 5: Solve for x
   x = 986,284.04/1,030.50
6. Step 6: Final answer
   x = 957.09