OPPOSITE RAYS: Two rays that are part of the same line and have only their endpoints in common.◦ Example: XZ and XY are opposite rays
STRAIGHT ANGLE: The figure formed byopposite rays
XY
Z
ANGLE: A figure where two rays have a common endpoint.
VERTEX: The common endpoint of an angle SIDES: The rays that make up an angle
S R
T
1
There are several ways to name the angle below.◦ Use the vertex and a point from each side
The vertex letter is always in the middle RST or TSR
◦ Use the vertex only If there is more than one angle at the vertex, then
you cannot use this method S
◦ Use a number Only useful when a number is given 1
S R
T
1
Name the angle below in four ways. Then identify its vertex and its sides.
4 Names: Vertex: Sides:
HI
G
3
GHI, IHG, H, 3H, 3
HG, HI
Name all angles having W as their vertex
By letters:
By numbers & letters:
RWS, SWT, TWU, RWT, SWU, RWU
3, 4, 5, RWT, SWU, RWU
An angle separates a plane into three parts: the INTERIOR of an angle, the EXTERIOR of an angle, and the angle itself.◦ In the figure to the right, point
W and all other points in blueare in the interior region
◦ Point V and all other points inthe beige area are in theexterior region
◦ Points X, Y, and Z are on the angle.
Tell whether each point is in the interior, exterior, or on the angle
D: E: F:
InteriorOnExterior
Assignment◦ Worksheet #3-1