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...
Texas Instruments
Texas Instruments: Geometric Representation of Trig Functions
Using similar triangles, a relationship is established between the six trigonometric functions of an angle and simple line segments. These relationships are then confirmed using line segment measurement capabilities of the graphing...