Question

What is a 30-60-90 triangle

Answer 1

It's a right triangle in which the two acute angles are  30°  and  60° .


In that kind of triangle, it's often handy and useful to remember that ...

-- the shorter leg is  =  1/2 of the hypotenuse
and
-- the longer leg is  =  (1/2 of the hypotenuse) · √3  .

Answer 2

The answer is a right triangle because of the right angle! Hope this helped :))