Finding the Fourth Proportional to 1,141.50, 1,575.30 and 644

Step by Step Solution

1. Step 1: Write the proportion equation
   1,141.50 : 1,575.30 = 644 : x
2. Step 2: Convert to fraction form
   1,141.50/1,575.30 = 644/x
3. Step 3: Cross multiply
   1,141.50x = 1,575.30 × 644
4. Step 4: Simplify right side
   1,141.50x = 1,014,493.20
5. Step 5: Solve for x
   x = 1,014,493.20/1,141.50
6. Step 6: Final answer
   x = 888.74