Question 976346
AB=(3-2,7-3)=(1,4)
You can use the dot product or trigonometry.
.
.
.


Dot product with unit x vector (1,0).
(1,4)*(1,0)=1*1+4*0=1
{{{A*B=abs(A)*abs(B)*cos(theta)}}}
{{{abs(A)=sqrt(1^2+4^2)=sqrt(1+16)=sqrt(17)}}}
{{{abs(B)=1}}}
{{{1=sqrt(17)*1*cos(theta)}}}
{{{cos(theta)=1/sqrt(17)}}}
{{{theta=75.96}}}
.
.
.
Using trigonometry,
{{{sin(theta)=y/sqrt(x^2+y^2)}}}
{{{sin(theta)=4/sqrt(1^2+4^2)}}}
{{{sin(theta)=4/sqrt(17)}}}
{{{theta=75.96}}}