Finding the Fourth Proportional to 1,016.64, 1,402.32 and 643.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,016.64 : 1,402.32 = 643.30 : x
2. Step 2: Convert to fraction form
   1,016.64/1,402.32 = 643.30/x
3. Step 3: Cross multiply
   1,016.64x = 1,402.32 × 643.30
4. Step 4: Simplify right side
   1,016.64x = 902,112.46
5. Step 5: Solve for x
   x = 902,112.46/1,016.64
6. Step 6: Final answer
   x = 887.35