Finding the Third Proportional to 145.69 and 316.69

Step by Step Solution

1. Step 1: Write the proportion equation
   145.69 : 316.69 = 316.69 : x
2. Step 2: Convert to fraction form
   145.69/316.69 = 316.69/x
3. Step 3: Cross multiply
   145.69x = 316.69 × 316.69
4. Step 4: Simplify right side
   145.69x = 100,290.97
5. Step 5: Solve for x
   x = 100,290.97/145.69
6. Step 6: Final answer
   x = 688.40