Which piano key matches the note on the staff?
F4
middle C
F3
A4

How to Find "Middle C". To find "middle C," look for the group of two black keys closest to the middle of the keyboard. "C" is the note directly on the left of those two black keys. "Middle C" is also the "C" closest to the brand name of the piano on the fall board. This note is called "middle C" for another reason.

Explanation:

How to Find "Middle C". To find "middle C," look for the group of two black keys closest to the middle of the keyboard. "C" is the note directly on the left of those two black keys. "Middle C" is also the "C" closest to the brand name of the piano on the fall board. This note is called "middle C" for another reason.

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.