Finding the Fourth Proportional to 1,105.42, 1,525.62 and 639.58

Step by Step Solution

1. Step 1: Write the proportion equation
   1,105.42 : 1,525.62 = 639.58 : x
2. Step 2: Convert to fraction form
   1,105.42/1,525.62 = 639.58/x
3. Step 3: Cross multiply
   1,105.42x = 1,525.62 × 639.58
4. Step 4: Simplify right side
   1,105.42x = 975,756.04
5. Step 5: Solve for x
   x = 975,756.04/1,105.42
6. Step 6: Final answer
   x = 882.70