Finding the Fourth Proportional to 1,030.08, 1,420.56 and 636.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,030.08 : 1,420.56 = 636.96 : x
2. Step 2: Convert to fraction form
   1,030.08/1,420.56 = 636.96/x
3. Step 3: Cross multiply
   1,030.08x = 1,420.56 × 636.96
4. Step 4: Simplify right side
   1,030.08x = 904,839.90
5. Step 5: Solve for x
   x = 904,839.90/1,030.08
6. Step 6: Final answer
   x = 878.42