Lines, Angles, and Shapes…Oh My!
Knowing the basics for lines, angles, and shapes will get you through the geometry section on the exam. Geometry is the study of the properties and relationships of lines, angles, and shapes.
Lines
A line has an indefinite length. Within the line, you might encounter points. A point is a specific location on the line. When a line is displayed an an example, there are usually two points represented through which the line passes. Since a line has an indefinite length, it is notated with arrows on both ends to represent that the line doesn’t end with the points.
If you took the two points with the line in the middle out of the line, you would have a line segment. On the other hand, if you took one of the points and the part where the line is indefinite, you would have a ray.
Angles
To make an angle, you must have two lines that intersect at some point. That intersection is called the vertex. Angles are measured by degrees. You probably already know some angles without realizing it. Let’s use a circle as an example. Although not an angle, a circle has a measurement of 360° . Within the circle, you can find many angles.
The circle above has a straight line through the middle and a right angle. Now let’s do the math. Since the circle is 360°, the line going straight through the middle is 180°. We know that because it represents half of the circle or 360/2. A half of a half-circle also known as a quarter is 90°. There are four quarters in a circle (90 x 4 = 360).
Shapes
A shape is a group of lines that form an enclosure. On the HiSet, you might encounter both two-dimensional and three-dimensional shapes. Two-dimensional shapes are flat (square). Three-dimensional shapes have a solid appearance (cube).
Similarity Versus Congruence
If two figures of the same shape are the same size, they are considered congruent; on the other hand, two figures of the same shape that are not the same size are considered similar.
