Finding the Third Proportional to 390.50 and 599.25

Step by Step Solution

1. Step 1: Write the proportion equation
   390.50 : 599.25 = 599.25 : x
2. Step 2: Convert to fraction form
   390.50/599.25 = 599.25/x
3. Step 3: Cross multiply
   390.50x = 599.25 × 599.25
4. Step 4: Simplify right side
   390.50x = 359,100.56
5. Step 5: Solve for x
   x = 359,100.56/390.50
6. Step 6: Final answer
   x = 919.59