Finding the Fourth Proportional to 1,105.53, 1,525.53 and 639.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,105.53 : 1,525.53 = 639.69 : x
2. Step 2: Convert to fraction form
   1,105.53/1,525.53 = 639.69/x
3. Step 3: Cross multiply
   1,105.53x = 1,525.53 × 639.69
4. Step 4: Simplify right side
   1,105.53x = 975,866.29
5. Step 5: Solve for x
   x = 975,866.29/1,105.53
6. Step 6: Final answer
   x = 882.71