(3)(17.25) = 51.75; he spent $51.75
Because everything in the problem is positive, no negative numbers are needed.
The answer to number eight is
That it would have to reflect in the middle and it has Proportional angles.
The reasons would be:
alternate interior angles
vertical angles
AAA (all angles are congruent)
Since we know that the two line segments are parallel, this means that BC is a transversal. Using that knowledge with the position of ABE and DCE, we see these are alternate interior angles.
AEB and DEC are vertical angles, since they share only a vertex.
This gives us 3 congruent angles, so the triangles must be similar.