Finding the Fourth Proportional to 1,108.90, 1,530.03 and 636.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,108.90 : 1,530.03 = 636.72 : x
2. Step 2: Convert to fraction form
   1,108.90/1,530.03 = 636.72/x
3. Step 3: Cross multiply
   1,108.90x = 1,530.03 × 636.72
4. Step 4: Simplify right side
   1,108.90x = 974,200.70
5. Step 5: Solve for x
   x = 974,200.70/1,108.90
6. Step 6: Final answer
   x = 878.53