a Use a protractor to rotate each ray of the angle.
B
b You can rotate three points making up the angle.
A
a Vertical angles
B
b Z
Practice makes perfect
a To complete the transformation, we need to rotate each ray around the given point by 180^(∘). We can do this by using a protractor.
We do the same thing for the second ray.
From the diagram, we see that the angle's sides form two pairs of opposite rays. This means the angles fits the description of vertical angles which means they have the same angle measure.
b To rotate the angle around the given point, we can rotate three points that make up the angle by 180^(∘) around the point of rotation. To do this, we will temporarily draw different colored points, one in the path of each ray.
Next, we have to rotate each of these endpoints by 180^(∘) around the point of rotation. Make sure the distance from the point of rotation is the same. We will begin by rotating the green point by 180^(∘) around the point of rotation.
We also have to rotate the two remaining points. Notice that they are at opposite ends of a ray. Therefore, when rotating them, they will simply exchange positions.
