Determine whether the relationship between the circumference of a circle and its diameter is a direct variation. if so, identify the constant of proportionality. justify your response.

The relationship between the circumference of a circle and its diameter represent  a direct variation

The constant of proportionality is equal to

Step-by-step explanation:

we know that

A relationship between two variables, x, and y, represent a direct variation if it can be expressed in the form or

The circumference of a circle is equal to

Let

C=y

D=x

substitute

therefore

The relationship between the circumference of a circle and its diameter represent  a direct variation

The constant of proportionality is equal to

since the airplane is moving with constant speed then the distance travelled can be calculated by x=u*t

in km/h would be:

x=640*3.5=2.240 km

in m/s would be:

u=640 km/h= 640.000 m/h =640.000/ 3600 m/s =177.8 m/s

t= 3.5 h= 3.5 * 3600 s=12.600 s

then x=u*t= 177.8*12.600= 2.240.280 m