Finding the Fourth Proportional to 1,236.52, 1,852.20 and 643.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,236.52 : 1,852.20 = 643.42 : x
2. Step 2: Convert to fraction form
   1,236.52/1,852.20 = 643.42/x
3. Step 3: Cross multiply
   1,236.52x = 1,852.20 × 643.42
4. Step 4: Simplify right side
   1,236.52x = 1,191,742.52
5. Step 5: Solve for x
   x = 1,191,742.52/1,236.52
6. Step 6: Final answer
   x = 963.79