<span>Ray
Q is the ray that angle PQR and SQR shares. Because both angles has the ray of
Q.
ray refers to a line with one endpoint
P is a ray, Q is a ray, R is a ray and S is a ray. When you put them together,
they form angle.
Pls. see attachment for the presentation of the angle PQR and SQR and how they
share ray Q</span>
The cost of each pen is $50, because you spend $600 on books leaving $200 to buy FOUR pens, making it $50 per pen