Draw a picture of an equilateral triangle. Cut the triangle in half, so that you get two 30-60-90 triangles. The area of these smaller triangles is 8 square inches.
The short leg of these triangles (the base) is half the side length: ½ s.
According to properties of 30-60-90 triangles, the long leg (the height) is √3 times the short leg: ½ s√3.
Area of a triangle is half the base times the height:
