Finding the Third Proportional to 139.25 and 299.88

Step by Step Solution

1. Step 1: Write the proportion equation
   139.25 : 299.88 = 299.88 : x
2. Step 2: Convert to fraction form
   139.25/299.88 = 299.88/x
3. Step 3: Cross multiply
   139.25x = 299.88 × 299.88
4. Step 4: Simplify right side
   139.25x = 89,925.02
5. Step 5: Solve for x
   x = 89,925.02/139.25
6. Step 6: Final answer
   x = 645.78