Curated OER
Finding the Area of an Equilateral Triangle
The problem seems simple: find the area of the equilateral triangle whose sides are each length 1. In fact, this same problem is solved in 8th grade, addressing a different Common Core standard, using the formula for area of a triangle...
Oswego City School District
Regents Exam Prep Center: Triangle Inequality Theorems
This tutorial discusses triangle inequality and provides practice problems for students to try out their skills. The teacher resource page contains a lesson plan for a yummy activity involving licorice.
Oswego City School District
Regents Exam Prep Center: Similarity of Triangles
Discover the world of "similarity" in this test prep tutorial on similar triangles. Detailed explanation of concept with examples, challenging interactive practice, and a classroom activity that integrates math and science.
Illustrative Mathematics
Illustrative Mathematics: G Srt Pythagorean Theorem
The purpose of this task is to prove the Pythagorean Theorem using similar triangles. Aligns with G-SRT.B.4.
Illustrative Mathematics
Illustrative Mathematics: G Srt Joining Two Midpoints of Sides of a Triangle
In this task, young scholars must prove that angles and triangles are congruent and that a parallel line passes through the midpoints of two sides of the larger triangle. Aligns with G-SRT.B.4.
CK-12 Foundation
Ck 12: Geometry: Pythagorean Theorem and Pythagorean Triples
[Free Registration/Login may be required to access all resource tools.] Apply the Pythagorean Theorem and its converse. Includes videos, exercises, links to interactive activities, etc.