Will the following measures form a triangle? 90° 12° 78° yes/no if yes, what type? if not, why not?

Yes with the given angles you can form a triangle.

Explanation:

For the formation of a triangle the basic theorem is to have sum of all the three angles equals to 180 degree. As the given angle's sum is equal to 180 degree so triangle can be constructed.

A triangle is categorized as right angle triangle when one of its angle is equal to 90 degree therefore the type of triangle will be right angle triangle.