Finding the Third Proportional to 213.56 and 291.56

Step by Step Solution

1. Step 1: Write the proportion equation
   213.56 : 291.56 = 291.56 : x
2. Step 2: Convert to fraction form
   213.56/291.56 = 291.56/x
3. Step 3: Cross multiply
   213.56x = 291.56 × 291.56
4. Step 4: Simplify right side
   213.56x = 85,008.69
5. Step 5: Solve for x
   x = 85,008.69/213.56
6. Step 6: Final answer
   x = 398.05