Respuesta :

3. A(r) = 4(pi symbol)r^2

r=4(pi symbol)A^2
r/4(pi symbol)=A^2

A=(sqaure root of)r/4(pi symbol)

4. d(v)=v^2/64

v=d^2/64

64v=d^2

(square root of)64v=d

Hope this helped!