Finding the Fourth Proportional to 1,053.72, 1,578.69 and 663.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,053.72 : 1,578.69 = 663.30 : x
2. Step 2: Convert to fraction form
   1,053.72/1,578.69 = 663.30/x
3. Step 3: Cross multiply
   1,053.72x = 1,578.69 × 663.30
4. Step 4: Simplify right side
   1,053.72x = 1,047,145.08
5. Step 5: Solve for x
   x = 1,047,145.08/1,053.72
6. Step 6: Final answer
   x = 993.76