What letter of the alphabet has a perpendicular line?

Many letters of the English alphabet have perpendicular lines. Perpendicular lines are like two lines making one corner of a square. So any letter that has two lines joined like the corner of a square has perpendicular lines.

These letters have right angles: E, F, f, H, I, L T, t, and sometimes X, x.

Keep in mind that the angles of the lines making the letters is effected by the font and whether or not the letter is italicized. For example, E is made of three perpendicular lines, but this 'E' has no perpendicular lines.