Finding the Fourth Proportional to 1,086.39, 1,628.71 and 436.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,086.39 : 1,628.71 = 436.50 : x
2. Step 2: Convert to fraction form
   1,086.39/1,628.71 = 436.50/x
3. Step 3: Cross multiply
   1,086.39x = 1,628.71 × 436.50
4. Step 4: Simplify right side
   1,086.39x = 710,930.82
5. Step 5: Solve for x
   x = 710,930.82/1,086.39
6. Step 6: Final answer
   x = 654.40