Finding the Fourth Proportional to 1,143.22, 1,577.50 and 639.06

Step by Step Solution

1. Step 1: Write the proportion equation
   1,143.22 : 1,577.50 = 639.06 : x
2. Step 2: Convert to fraction form
   1,143.22/1,577.50 = 639.06/x
3. Step 3: Cross multiply
   1,143.22x = 1,577.50 × 639.06
4. Step 4: Simplify right side
   1,143.22x = 1,008,117.15
5. Step 5: Solve for x
   x = 1,008,117.15/1,143.22
6. Step 6: Final answer
   x = 881.82