In the diagram, the question asks if side $d$ can be the base of the triangle. If side $d$ is the base, the corresponding height must be a perpendicular distance from the opposite vertex to the line containing side $d$.

Looking at the diagram:

• Side $d$ is slanted, and the height must be perpendicular to this side if it is chosen as the base.
• There is a vertical dashed line labeled $g$, which is perpendicular to side $d$, indicating that $g$ is the height when $d$ is taken as the base.

Thus, yes, side $d$ can be the base, and the corresponding height would be the length $g$, which is the perpendicular distance from the opposite vertex to the line containing $d$.

Would you like more details, or do you have any further questions?

Here are some related questions you might consider:

1. What is the significance of choosing different sides as the base in a triangle?
2. How do you calculate the area of a triangle using different bases and heights?
3. Why is it important that the height be perpendicular to the base?
4. How would the height change if side $e$ or side $f$ were chosen as the base instead of $d$?
5. Can any side of a triangle be chosen as the base, and how does that affect calculations?

Tip: The area of a triangle is always calculated using the formula $\text{Area} = \frac{1}{2} \times \text{Base} \times \text{Height}$, where the height must always be perpendicular to the base!