Finding the Fourth Proportional to 1,016.35, 1,401.99 and 643.18

Step by Step Solution

1. Step 1: Write the proportion equation
   1,016.35 : 1,401.99 = 643.18 : x
2. Step 2: Convert to fraction form
   1,016.35/1,401.99 = 643.18/x
3. Step 3: Cross multiply
   1,016.35x = 1,401.99 × 643.18
4. Step 4: Simplify right side
   1,016.35x = 901,731.93
5. Step 5: Solve for x
   x = 901,731.93/1,016.35
6. Step 6: Final answer
   x = 887.23