Finding the Fourth Proportional to 1,070.48, 1,603.59 and 660.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,070.48 : 1,603.59 = 660.42 : x
2. Step 2: Convert to fraction form
   1,070.48/1,603.59 = 660.42/x
3. Step 3: Cross multiply
   1,070.48x = 1,603.59 × 660.42
4. Step 4: Simplify right side
   1,070.48x = 1,059,031.59
5. Step 5: Solve for x
   x = 1,059,031.59/1,070.48
6. Step 6: Final answer
   x = 989.31