Finding the Fourth Proportional to 1,036.10, 1,429.89 and 643.25

Step by Step Solution

1. Step 1: Write the proportion equation
   1,036.10 : 1,429.89 = 643.25 : x
2. Step 2: Convert to fraction form
   1,036.10/1,429.89 = 643.25/x
3. Step 3: Cross multiply
   1,036.10x = 1,429.89 × 643.25
4. Step 4: Simplify right side
   1,036.10x = 919,776.74
5. Step 5: Solve for x
   x = 919,776.74/1,036.10
6. Step 6: Final answer
   x = 887.73