By its sides and angles · Alberta Grade 4 · maddyhelps.com
Use the measurements written on each shape — equal side lengths, right-angle squares and angle sizes — to write the most exact name. Four sides first, then triangles.
Acute: less than 90°
Right: exactly 90°
Obtuse: more than 90°
Name that shape
square, rectangle, rhombus, parallelogram, trapezoid, equilateral triangle, isosceles triangle, scalene triangle, right triangle, obtuse triangle. The square is also a rectangle and a rhombus, and square is the most exact name. For triangles there are two ways to sort: by sides (the first three) and by angles (the last two).
The measurements are the evidence. A shape that looks square but is marked 5 cm and 6 cm is a rectangle — which is the habit Alberta's outcome is after: using measurements, not appearance.
Why this matters is on the numbers to 10 000 page. More sheets