Finding the Third Proportional to 139.69 and 289.50

Step by Step Solution

1. Step 1: Write the proportion equation
   139.69 : 289.50 = 289.50 : x
2. Step 2: Convert to fraction form
   139.69/289.50 = 289.50/x
3. Step 3: Cross multiply
   139.69x = 289.50 × 289.50
4. Step 4: Simplify right side
   139.69x = 83,810.25
5. Step 5: Solve for x
   x = 83,810.25/139.69
6. Step 6: Final answer
   x = 599.98