Lesson · Grade 6 · Mathematics
Combining Two Transformations
- Grade 6
- Mathematics
- 1 min 18 s
- British Columbia
- BC6-MA-42
Triangle ABC is moved 5 units right on a grid, and that first image A′B′C′ is then reflected in a mirror line to make the final image A″B″C″. The video shows that the second transformation always starts from the image the first one made, and that the two prime marks mean two transformations have been done.
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In one sentence
The question this lesson answers
We can combine two transformations by doing one after the other.
Let us translate triangle A B C 5 units right, then reflect it in the mirror line.
Transcript
What the lesson says
We can combine two transformations by doing one after the other.
Let us translate triangle A B C 5 units right, then reflect it in the mirror line.
Step one is the translation. Slide the whole triangle 5 units to the right.
This gives the first image, A prime B prime C prime.
Step two starts from this new image, not from the triangle we began with.
A prime and B prime are each 3 units above the mirror line.
So their images go 3 units below it.
C prime is 1 unit above the line, so its image is 1 unit below it.
Join the new corners to draw the final image, A double prime B double prime C double prime.
The two prime marks show that two transformations have been done.
Fold along the mirror line, and the first image lands exactly on the final image.
The final image is the same size and shape as A B C, but it is flipped over.
To combine two transformations, do the first one, then do the second one to its image.
Curriculum
Where this fits
- British Columbia, Grade 6
Mathematics, Geometry and measurement: combinations of transformationsBC6-MA-42
- British Columbia, Grade 7
Mathematics, Geometry and measurement: combinations of transformationsBC7-MA-62
Previous: Rotations: Turning a Shape About a PointNext: Does the Order of Transformations Matter?
This lesson is also listed in Grade 7.
The outcomes and strands follow the British Columbia curriculum.
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