Finding the Third Proportional to 288.50 and 435.50

Step by Step Solution

1. Step 1: Write the proportion equation
   288.50 : 435.50 = 435.50 : x
2. Step 2: Convert to fraction form
   288.50/435.50 = 435.50/x
3. Step 3: Cross multiply
   288.50x = 435.50 × 435.50
4. Step 4: Simplify right side
   288.50x = 189,660.25
5. Step 5: Solve for x
   x = 189,660.25/288.50
6. Step 6: Final answer
   x = 657.40