Problem – Geometry. How to calculate the area of an equilateral triangle, given its height. In this problem, we explain the solution to this student’s question for the specific case when the height of the triangle is 6 cm, using two 30-60-90 special triangles. You can repeat this process to find that the area of any equilateral triangle with height is .

As we mention in our response to this student, we have been experimenting with video responses to questions, and provided one to help see the geometry.