Transformations on the Coordinate Plane
Aligned to 8.G.A.3 — Common Core State Standards for Mathematics.
What this lesson teaches
Using coordinates: a translation adds to x or y; a reflection across an axis changes a sign; a rotation about the origin swaps and/or negates coordinates; and a dilation multiplies each coordinate by a scale factor k, changing the size.
Worked example
Dilate point (2, 3) by scale factor k = 3 about the origin by multiplying each coordinate by 3, giving (6, 9). The point moves 3 times farther from the origin, so the figure grows 3 times larger.
Practice questions
- Dilate (4, −2) by a scale factor of 2 about the origin.
- Reflect (−3, 5) across the y-axis.
- A triangle is dilated by k = 1/2. How do its side lengths change?
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Transformaciones en el Plano Cartesiano
Usando coordenadas: una traslación suma a x o a y; una reflexión sobre un eje cambia un signo; una rotación alrededor del origen intercambia o niega coordenadas; y una dilatación multiplica cada coordenada por un factor de escala k, cambiando el tamaño.
Ejemplo: Dilata el punto (2, 3) por un factor de escala k = 3 alrededor del origen multiplicando cada coordenada por 3, lo que da (6, 9). El punto se aleja 3 veces más del origen, así que la figura crece 3 veces más grande.
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