Angle A measures to 59 degrees.
Step-by-step explanation:
Recall that

Therefore,

so


Consider the contrapositive of the statement you want to prove.
The contrapositive of the logical statement
<em>p</em> ⇒ <em>q</em>
is
¬<em>q</em> ⇒ ¬<em>p</em>
In this case, the contrapositive claims that
"If there are no scalars <em>α</em> and <em>β</em> such that <em>c</em> = <em>α</em><em>a</em> + <em>β</em><em>b</em>, then <em>a₁b₂</em> - <em>a₂b₁</em> = 0."
The first equation is captured by a system of linear equations,

or in matrix form,

If this system has no solution, then the coefficient matrix on the right side must be singular and its determinant would be

and this is what we wanted to prove. QED
<u>Parallel lines</u> are lines that run side-by-side without touching or intersecting!
<u>Perpendicular lines</u> intersect/cross and can also make 90° angles (those little green boxes in the picture) in their corners!
Sets of parallel lines:
Sets of perpendicular lines: