More triads

Triad means chord built with thirds. A triad is a group of three notes played or sung together. It is a music theory term for a chord of three notes; it consist a root or first, a third and a fifth. We say that triads are built out of thirds, because the interval between the lowest note and the middle note is a third, and the interval between the middle note and the highest note is also a third.
The following are guidelines in constructing a triad without inversions:
Draw the stave
Draw the clef
Insert the key signature if you’re meant to use key signature; if not, go to the next step
Draw the triad starting from the root except where asked to do otherwise.
Insert the accidental sign
Close the stave with a double bar line

Example: construct the tonic triad of D major on treble stave using accidental
The scale of G major is given as D E F G A B C D. The tonic is the first note of the scale. Since we’re in D major, the tonic is D. That is going to be the first note we write down. It’s going to be the lowest note of the triad, so we’ll write a low G, so that we have plenty of rooms to add notes above it.The next note in the triad is the third and the third note in the scale is F, so we add that one too.The last note in the triad is the fifth and the fifth note in the scale is A.

Here is our finished tonic triad of D major:
Note: when constructing a triad with key signature, you fix in the key signature before constructing the triad.
Note: the same procedure goes for the construction on dominant triads. The dominant is the fifth note in the triad and automatically becomes the root of the triad. Using the above question, the dominant triad would be:

A triad is inverted when a note other than the root is acting as the bass note. Two inversions are possible: the third as the bass note or the fifth as the bass note. When the root is in the bass the triad is said to be in root position. When the third is in the bass the triad is in first inversion and when the fifth is in the bass the triad is in second inversion.
A system of numbers is used along with roman numerals to indicate when triads are inverted. When a triad is in first inversion the number "6" is placed after the roman numeral and when a triad is in second inversion the numbers "6" and "4" are placed after the roman numeral. (No number after the roman numeral means that the triad is in root position.)

The numbers after the roman numerals are a representation of intervals found above the bass note. The notes represented by the numbers can be played in any octave above the bass note.
No numbers after the roman numeral in the root position triad actually means that notes a third and a fifth are located above the bass note. The 6 in the first inversion roman numeral symbol means that notes a sixth and a third are located above the bass note. The 6 and 4 in the second inversion roman numeral symbol mean that notes a sixth and a fourth are located above the bass note.