Finding the Third Proportional to 123.50 and 288.50

Step by Step Solution

1. Step 1: Write the proportion equation
   123.50 : 288.50 = 288.50 : x
2. Step 2: Convert to fraction form
   123.50/288.50 = 288.50/x
3. Step 3: Cross multiply
   123.50x = 288.50 × 288.50
4. Step 4: Simplify right side
   123.50x = 83,232.25
5. Step 5: Solve for x
   x = 83,232.25/123.50
6. Step 6: Final answer
   x = 673.95