
David W. answered 04/23/19
Experienced Prof
"the midpoint of the base is at the origin" and "side 2a"
So, two vertices are at ( -a, 0 ) and ( a, 0 ).
The equilateral triangle is divided into two right triangles (aso the Pythagorean Theorem applies). Two sides are known: base = a and hypotenuse = 2a2
Using the Pythagorean theorem, the third side (on the y-axis is a√3.
(a2) + (a√3)2 = (2a)2
a2 + 3a2 = 4a2
The third vertex is at ( 0, a√3 )