Explain the difference between an equilateral, an isosceles, and a scalene triangle.

An equilateral triangle has 3 equal sides, an isosceles triangle has 2 equal sides, and a scalene triangle has no equal sides.

Can a triangle be both a right triangle and an equilateral triangle? Explain why or why not.

No, a triangle cannot be both a right triangle and an equilateral triangle because an equilateral triangle must have three acute angles.

Grade 5th Grade · Math · 20 min

I can classify triangles by their sides and angles.

mathantics · 7:40

Math Antics - Triangles

3 key concepts

1
Triangles are polygons that always have 3 sides and 3 angles; the word ‘triangle’ means 3 angles.
2
Triangles can be classified by their sides and by their angles.
3
If all three sides of a triangle are the same length, it is an equilateral triangle; if only two sides are equal, it is an isosceles triangle; and if no sides are equal, it is a scalene triangle.

3 questions · Multiple choice & Short answer

Quick comprehension check

“Draw an example of each of the following triangles: acute isosceles, obtuse scalene, and right scalene. Label each triangle with its type.”

Get all 3 ready-to-use resources:

Teacher GuideComplete lesson plan

Student DocPrintable student handouts

SlidesReady-to-use presentation