Happy π day ! (Oh Happy Day parody)

To celebrate π day on the 3.14.15 (march 14, 2015) in Marseille, the concert band "Ensemble Musical du Sud", together with the choir of the black eyed π interpreted "Happy π day !", a rewritten version of the gospel classic "Oh Happy Day !". Below are the lyrics.
Section A :
Oh happy day
Oh happy day
Happy pi day
Happy pi day
The circumference
Of the circle
The circumference
Of the circle
The circumference
Of the circle
Is pi times the di-ameter
Happy pi day
Happy pi day
Section A' :
Oh happy day
Oh happy day
Happy pi day
Happy pi day
The area
Of the circle
The area
Of the circle
The area
Of the circle
Is pi time the radi-us squared
Happy pi day
Happy pi day
Section B :
It taught me how
To search
Find and prove
Find and prove
And inte-graaaa-ting
Eve-ry day
Eve-ry day
Back to A'
Section C :
Happy pi day
Happy pi day
Happy pi day
Happy pi day
Happy pi day
Happy pi day
Happy pi day
Happy pi day
Section D :
Happy pi day
Happy pi day
Happy pi day
Happy pi day
Section E :
1) 3.14 1592
Three point one four
One five nine two
2) 6535 8979
Six five three five
Eight nine s'ven nine
3) 3238 4626
Three two three eight
Four six two six
4) 4338 3279
Four three three eight
Three two s'ven nine
5) 5028 8419
Five O two eight
Eight four one nine
6) 7169 3993
S'ven one six nine
Three nine nine three
Back to A and finale.

[@Harlem55]

This blows... in every way.