Finding the Fourth Proportional to 1,036.39, 1,429.57 and 643.41

Step by Step Solution

1. Step 1: Write the proportion equation
   1,036.39 : 1,429.57 = 643.41 : x
2. Step 2: Convert to fraction form
   1,036.39/1,429.57 = 643.41/x
3. Step 3: Cross multiply
   1,036.39x = 1,429.57 × 643.41
4. Step 4: Simplify right side
   1,036.39x = 919,799.63
5. Step 5: Solve for x
   x = 919,799.63/1,036.39
6. Step 6: Final answer
   x = 887.50