Finding the Fourth Proportional to 1,016.31, 1,402.38 and 643.53

Step by Step Solution

1. Step 1: Write the proportion equation
   1,016.31 : 1,402.38 = 643.53 : x
2. Step 2: Convert to fraction form
   1,016.31/1,402.38 = 643.53/x
3. Step 3: Cross multiply
   1,016.31x = 1,402.38 × 643.53
4. Step 4: Simplify right side
   1,016.31x = 902,473.60
5. Step 5: Solve for x
   x = 902,473.60/1,016.31
6. Step 6: Final answer
   x = 887.99