A very pretty thing am I, fluttering in the pale-blue sky. Delicate, fragile on the wing, indeed I am a pretty thing. What am I?

butterfly im just built different

Explanation:

answer; timpani,horns and bells;

coordinates of r(b,c)

slope of nm is 0.

step-by-step explanation:

the midpoint of the line joining the points (x₁,y₁) and (x₂,y₂) is given by

the midpoint of the line segment nk is given by

∴r(b,c)

the slope of the line joining the points (x₁,y₁) and (x₂,y₂) is given by

slope of rs is

hence

coordinates of r(b,c)

and slope of nm is 0.