To simplify the expression \( 9 + 1.34 + \frac{1}{2} (3.50 + 1.74) \), we can follow these steps:
Step 1: Simplify the parentheses
Start by simplifying the expression inside the parentheses:
\[ 3.50 + 1.74 = 5.24 \]
Step 2: Substitute back into the expression
Now substitute \( 5.24 \) back into the original expression:
\[ 9 + 1.34 + \frac{1}{2} (5.24) \]
Step 3: Calculate the half of the sum
Next, calculate \( \frac{1}{2} \times 5.24 \):
\[ \frac{1}{2} \times 5.24 = 2.62 \]
Step 4: Substitute again
Now substitute \( 2.62 \) back into the expression:
\[ 9 + 1.34 + 2.62 \]
Step 5: Add all the terms
Now, add all the terms together:
- First add \( 9 + 1.34 \):
\[ 9 + 1.34 = 10.34 \]
- Then add \( 10.34 + 2.62 \):
\[ 10.34 + 2.62 = 12.96 \]
Conclusion
Thus, the simplified expression is:
\[ \boxed{12.96} \]