Hand motions are essential for student comprehension and retention of the concepts in this song.
For the equilateral verse, students form an equilateral triangle using both index fingers and thumbs. When singing "3 congruent sides" the kids hold up three fingers.
For the isosceles verse, students from two sides of the triangle only, using their arms in an A-frame sort of configuration. When singing "2 congruent sides" the kids hold up two fingers.
For the scalene triangle, students use their index finger on one hand to draw a random triangle in the air in time with the music, like this: 1-SCA 2-LENE 3-SCA (Freeze) 1-TRI 2-ANG 3-GLE, 1-TRI 2-ANG 3-GLE, 1-TRI 2-ANG 3-GLE. There is only one ''G'' in ''triangle'' but the sound is basically heard twice as you sing it. When the kids sing "no congruent sides" they wag their fingers in the air like a scolding mother.
For the right triangle, students form a little right triangle using the thumb and forefinger on one hand in a capital ''L'' shape and an extended opposite hand to form the third side of the triangle.
Watch 'Triangle Song' Hand Motion Video