Classifying Triangles by Sides & Angles Acute Right Obtuse
by Making Algebra Fun by Angela Dougher © 2026
Premier Publisher
Price: $2 USD
Subjects: math,mathHighSchool,highSchoolGeometry,congruence
Grades: 9,10
Description
Students classify triangles by their sides and by their angles with 25 self-checking digital task cards. Each card shows lettered choices, and students type the letter of the correct answer. Skills covered: Classifying by angles: acute, right, obtuse Classifying by sides: scalene, isosceles, equilateral Reading tick marks and right-angle marks Finding the third angle, then classifying Side lengths and angle measures with variables Classifying by sides and angles together Triangles inside larger figures: split triangles, rectangles, squares, and intersecting segments Using exterior angles, linear pairs, vertical angles, and parallel lines to find the angles first Cards 1–15 use a single triangle and progress from reading a diagram to finding the third angle and substituting for x. Cards 16–25 use more complex diagrams, where students find missing angles in a larger figure before they classify. The deck works for independent practice, homework, stations, review, and sub plans. Each card includes alt text for screen reader users. Problems and alt text were created with the help of AI (Claude by Anthropic) and reviewed by the author for accuracy.