Now that we know how to rotate a point, let’s look at rotating a figure on the coordinate grid.
Let’s look at a real example, here we plotted point A at \((5,6)\) then we rotated the paper 90° clockwise to create point A’, which is at \((6,-5)\). If you take a coordinate grid and plot a point, then rotate the paper 90° or 180° clockwise or counterclockwise about the origin, you can find the location of the rotated point. Let’s start by looking at rotating a point about the center \((0,0)\). Here is a figure rotated 90° clockwise and counterclockwise about a center point.Ī great math tool that we use to show rotations is the coordinate grid. We specify the degree measure and direction of a rotation. The angle of rotation is usually measured in degrees. The measure of the amount a figure is rotated about the center of rotation is called the angle of rotation. Another great example of rotation in real life is a Ferris Wheel where the center hub is the center of rotation. A figure can be rotated clockwise or counterclockwise. A figure and its rotation maintain the same shape and size but will be facing a different direction. We call this point the center of rotation. More formally speaking, a rotation is a form of transformation that turns a figure about a point. There are other forms of rotation that are less than a full 360° rotation, like a character or an object being rotated in a video game. The wheel on a car or a bicycle rotates about the center bolt. The earth is the most common example, rotating about an axis. But points, lines, and shapes can be rotates by any point (not just the origin)! When that happens, we need to use our protractor and/or knowledge of rotations to help us find the answer.Hello, and welcome to this video about rotation! In this video, we will explore the rotation of a figure about a point. The rotation rules above only apply to those being rotated about the origin (the point (0,0)) on the coordinate plane. If we compare our coordinate point for triangle ABC before and after the rotation we can see a pattern, check it out below: To derive our rotation rules, we can take a look at our first example, when we rotated triangle ABC 90º counterclockwise about the origin. Rotation Rules: Where did these rules come from? Yes, it’s memorizing but if you need more options check out numbers 1 and 2 above! Know the rotation rules mapped out below.Use a protractor and measure out the needed rotation.We can visualize the rotation or use tracing paper to map it out and rotate by hand.
There are a couple of ways to do this take a look at our choices below: Let’s take a look at the difference in rotation types below and notice the different directions each rotation goes: How do we rotate a shape? Rotations are a type of transformation in geometry where we take a point, line, or shape and rotate it clockwise or counterclockwise, usually by 90º,180º, 270º, -90º, -180º, or -270º.Ī positive degree rotation runs counter clockwise and a negative degree rotation runs clockwise.