To find the area of a Canadian football field, we can add the area of the American football field to the additional area that the Canadian field has.
Given:
- Area of an American football field = \(6.4 \times 10^3\) yd²
- Additional area for a Canadian football field = 3350 yd²
First, we need to express 3350 in scientific notation:
\[ 3350 = 3.35 \times 10^3 \]
Now we can add the two areas together:
\[ \text{Area of Canadian football field} = 6.4 \times 10^3 + 3.35 \times 10^3 \]
Since both numbers are in scientific notation with the same exponent (10³), we can simply add the coefficients:
\[ \text{Area} = (6.4 + 3.35) \times 10^3 = 9.75 \times 10^3 \text{ yd}² \]
Now, writing it in scientific notation to two decimal places, the area of a Canadian football field is:
\[ \boxed{9.75 \times 10^3 \text{ yd}²} \]