Acarpenter has constructed a chair like the one shown below describe the type of lines formed by the front edge of the seat and the back leg

the lines formed by the front edge of the seat and the back leg are perpendicular lines.

You can see the chair in the picture attached.

Let's see two important definitions:
- parallel lines are lines that don't share any common point, which means that they never intersect;
- perpendicular lines are lines that when they cross each other form 4 right angles.

According to these definitions, looking at the picture, we can say that:
- the line formed by the front edge is parallel to the line formed by the back edge;
- the line formed by the back edge is perpendicular to the lines formed by each of the back legs.

Applying the transitive property, we can say that the line formed by the front edge is perpendicular to the lines formed by each of the back legs.