SME
Grade 8 Math
Geometry
Translations, rotations, reflections and dilations
Main lesson
Reflection
Use this for “(3, 7) is reflected over the y-axis. Where is its image?”
Reflection over a horizontal line
Use this for “(3, 7) is reflected over the x-axis. Where is its image?”
Rotation about the origin
Use this for “Rotate (3, 1) by 90° counterclockwise about (0, 0).”
Dilation
Use this for “Dilate (1, 1) from the origin by a scale factor of 3.”
Similar triangles
Use this for “Two triangles are similar. One has sides 8, 12 and x; the matching sides of the other are 6, y and 12. Find x and y.”
Which move?
Use this for “Is it a flip, a slide or a turn?”
Congruent, similar or neither?
Use this for “Which figures are congruent to the first? Which are only similar?”
Pythagorean theorem and distance between points
Main lesson
Distance between two points
Use this for “Find the distance between (−9, −12) and (0, 0)” or “How long is the segment on the grid?”
A diagonal through a box
Use this for “Will a 30 cm umbrella fit flat in a 20 cm by 15 cm by 18 cm box, corner to corner?”
Is it a right triangle?
Use this for “Which of these could be the sides of a right triangle?” with the converse of the Pythagorean theorem.
Volume of cylinders, cones and spheres
Main lesson
Volume of a cone
Use this for “A cone has radius 3 and height 7. What is its volume?” or “A cone holds 18π with height 6: its radius?”
Volume of a sphere
Use this for “A ball of radius 3 cm: its volume” or “A ball just fits in a 4-inch box: is its volume more or less than half of 4³?”
Change one dimension
Use this for “A cylinder holds 60π cm³. What does it hold at 3 times the height?” or “Quadruple the radius of a cone.”
Which volume formula?
Use this for “Which formula finds the volume of a funnel?”