Proof of ∠QOR = 90° + ∠P/2
As PQR is a Δ, ∠P + ∠Q + ∠R = 180°.
So ∠Q + ∠R = 180° - ∠P
(∠Q + ∠R)/2 = 90° - ∠P/2
In ΔQOR, ∠OQR + ∠ORQ + ∠QOR = 180°
∠Q /2 + ∠ R/2 + ∠QOR = 180°
Substituting from (1): 90 - ∠P/2 + ∠QOR = 180°
∠QOR = 90° + P/2
Writing mathematical and simple equations on placards is to
attract the attention of the public in a new way. Also it means to
attract children and students towards the slogan "Save Girl Child, Save
Further, it also means that girls can do maths also. The triangle
is a symbol for the family. Wide at one vertex, Husband at one vertex and
the children at the third vertex.
A girl or women is symbolized by the triangle. One part is
herself. The other part is the future of mankind. Because it is the
girl who will give birth to future men and women. So if girls
are killed in the womb itself (foeticide) then future of the human race will be
See the diagram too.