Video Transcript
Name the angle formed by ray 𝐹𝐶
and ray 𝐹𝐵.
In the picture, we can see several
rays. We know that a ray starts from an
endpoint and then continues in one direction. For example, the ray 𝐹𝐴 starts at
this point here, continues through point 𝐴, and this arrowhead on the end shows
that we’re talking about a ray because it continues on and on in a single
direction.
Now, our question talks about two
other rays that we can see in the diagram: ray 𝐹𝐶 and ray 𝐹𝐵. How do we know that these symbols
represent rays? Well, if we think about the first
one for a moment, we can see two letters. The first letter is our
endpoint. The second letter is a point that
our ray travels through. And importantly, on top of them, we
can see an arrow pointing in one direction.
Let’s try and find this ray on the
diagram. It begins at point 𝐹. It travels through point 𝐶 and
continues out the other side, on and on and on. So where’s our second ray, ray
𝐹𝐵? Well, once again, we’re starting
from the same point, point 𝐹. This time though, we’re going to
travel through point 𝐵 on and on beyond point 𝐵. So our question mentions two rays,
but did you notice they share an endpoint? And that’s point 𝐹 here. And we know that where two rays
meet at a single endpoint, they make an angle.
Now, our question asks us to name
this angle. We could look at the vertex and
write the symbol for angle and then just the letter 𝐹. And we could say that we’re talking
about angle 𝐹. But there are lots of angles in
this diagram, and they’ve all got 𝐹 as their vertex. We’re going to have to list all
three points, and we’re going to write the vertex in the middle. So if we want to name this angle,
we could start by writing the angle sign and then write point 𝐵, then 𝐹, that’s
the vertex of our angle, and finally 𝐶. We can represent the angle formed
by rays 𝐹𝐶 and 𝐹𝐵 by drawing the angle symbol and then writing the letters
𝐵𝐹𝐶.