Question

In a major key, major triads can be built on which scale degrees?

Answer 1

Tonic - Mediant - Dominant.

Answer 2

What part had you stumped? Do you need some extra help?

Answer 3

On the root, third, and fifth...I'm pretty sure :)

Answer 4

I think he means: if you build a triad starting from each degree of the major scale, which scale degrees produce major triads.

The answer to that would be 1, 4 and 5; tonic, subdominant and dominant.