Finding the Third Proportional to 145.69 and 315.28

Step by Step Solution

1. Step 1: Write the proportion equation
   145.69 : 315.28 = 315.28 : x
2. Step 2: Convert to fraction form
   145.69/315.28 = 315.28/x
3. Step 3: Cross multiply
   145.69x = 315.28 × 315.28
4. Step 4: Simplify right side
   145.69x = 99,402.27
5. Step 5: Solve for x
   x = 99,402.27/145.69
6. Step 6: Final answer
   x = 682.30