Rotation — Grade 8 Math, what it means and where it is taught
A turn about a fixed point, through a given angle and direction.
Taught in Grade 8 Math.
Where it is taught
Practise this idea
2 questions in the course bank use Rotation, in Translations, Reflections & Rotations.
Problem 1
Reflect (a, b) across the x-axis, then across the y-axis. Give the result.
Worked answer
(-a, -b)
Across the x-axis: (a, -b)
Across the y-axis: (-a, -b)
Same as a 180° rotation
Problem 2
Triangle ABC has A(1, 2), B(5, 2), C(1, 6). Its image is A'(2, -1), B'(2, -5), C'(6, -1). Which transformation was used?
Worked answer
rotation of 90 degrees clockwise about the origin
A(1,2) → (2, -1) ✓
B(5,2) → (2, -5) ✓
C(1,6) → (6, -1) ✓
That rule is a 90° clockwise rotation, also called 270° counter-clockwise