Finding the Fourth Proportional to 1,015.52, 1,401.42 and 643.16

Step by Step Solution

1. Step 1: Write the proportion equation
   1,015.52 : 1,401.42 = 643.16 : x
2. Step 2: Convert to fraction form
   1,015.52/1,401.42 = 643.16/x
3. Step 3: Cross multiply
   1,015.52x = 1,401.42 × 643.16
4. Step 4: Simplify right side
   1,015.52x = 901,337.29
5. Step 5: Solve for x
   x = 901,337.29/1,015.52
6. Step 6: Final answer
   x = 887.56