Understanding 90° Counterclockwise Rotation

The video tutorial explains how to rotate a triangle 90° counterclockwise about the origin. It begins by plotting the initial points of the triangle and then discusses the assumptions for rotation direction and point. The tutorial demonstrates how to apply the rotation by swapping and negating coordinates, and finally, it shows how to plot the new points after rotation.

What is the first step in rotating a triangle 90°?

• Label the points

• Plot the points

• Draw the triangle

• Calculate the area

Tags

CCSS.8.G.A.3

CCSS.HSG.CO.A.5

When rotating a shape 90°, what is the default direction if not specified?

• Clockwise

• Counterclockwise

• Upwards

• Downwards

Tags

CCSS.8.G.A.3

CCSS.HSG.CO.A.5

What assumption is made about the point of rotation if not specified?

• About the bottom-right corner

• About the top-left corner

• About the origin

• About the center of the shape

Tags

CCSS.8.G.A.3

CCSS.HSG.CO.A.5

How do you transform the coordinates (x, y) when rotating 90° counterclockwise?

• Negate y only

• Negate x and y

• Swap x and y, negate y

• Swap x and y, negate x

Tags

CCSS.8.G.A.3

CCSS.HSG.CO.A.5

What is the new coordinate of point J (2, 6) after a 90° counterclockwise rotation?

• (-6, 2)

• (6, -2)

• (-2, 6)

• (2, -6)

Tags

CCSS.8.G.A.3

CCSS.HSG.CO.A.5

What is the new coordinate of point K (5, 2) after a 90° counterclockwise rotation?

• (2, -5)

• (-2, 5)

• (-5, 2)

• (5, -2)

Tags

CCSS.8.G.A.3

CCSS.HSG.CO.A.5

What is the new coordinate of point L (7, 5) after a 90° counterclockwise rotation?

• (-7, 5)

• (7, -5)

• (5, -7)

• (-5, 7)

Tags

CCSS.8.G.A.3

CCSS.HSG.CO.A.5

After rotating the triangle, what should you do next?

• Erase the original points

• Plot the new points

• Calculate the perimeter

• Change the triangle's color

Tags

CCSS.8.G.A.3

CCSS.HSG.CO.A.5

What is the final step in the rotation process?

• Re-draw the triangle

• Check the rotation angle

• Verify the new coordinates

• Label the new points

Tags

CCSS.8.G.A.3

CCSS.HSG.CO.A.5