Finding the Third Proportional to 151.78 and 216.56

Step by Step Solution

1. Step 1: Write the proportion equation
   151.78 : 216.56 = 216.56 : x
2. Step 2: Convert to fraction form
   151.78/216.56 = 216.56/x
3. Step 3: Cross multiply
   151.78x = 216.56 × 216.56
4. Step 4: Simplify right side
   151.78x = 46,899.32
5. Step 5: Solve for x
   x = 46,899.32/151.78
6. Step 6: Final answer
   x = 308.99