When you play something like a common C chord or G chord on your guitar you are actually playing a major chord or major triad. They are just different names used to describe the same thing. A triad is a chord consisting of three notes. The previous page showed us how chords are built from the major scale by stacking the notes in thirds. A triad is created by taking the first three of these notes. Therefore a major triad consists of the first, third and fifth of the major scale.
The example below shows how this applies to the C major scale to create a C major triad
As you can see, chords are built around the major scales. The scale notes are referenced often when talking about chords. We use the scale degrees to let us know what notes belong to a chord.
The major chord is quite simply built from the first, third and fifth degrees of the major scale.