Finding the Fourth Proportional to 1,174.50, 1,620.82 and 643.36

Step by Step Solution

1. Step 1: Write the proportion equation
   1,174.50 : 1,620.82 = 643.36 : x
2. Step 2: Convert to fraction form
   1,174.50/1,620.82 = 643.36/x
3. Step 3: Cross multiply
   1,174.50x = 1,620.82 × 643.36
4. Step 4: Simplify right side
   1,174.50x = 1,042,767.54
5. Step 5: Solve for x
   x = 1,042,767.54/1,174.50
6. Step 6: Final answer
   x = 887.84