Finding the Third Proportional to 307.69 and 613.69

Step by Step Solution

1. Step 1: Write the proportion equation
   307.69 : 613.69 = 613.69 : x
2. Step 2: Convert to fraction form
   307.69/613.69 = 613.69/x
3. Step 3: Cross multiply
   307.69x = 613.69 × 613.69
4. Step 4: Simplify right side
   307.69x = 376,612.35
5. Step 5: Solve for x
   x = 376,612.35/307.69
6. Step 6: Final answer
   x = 1,224.01