C
the explanation is in the photo
54554/99999. I think I am right but sorry if I am wrong.
m∡A = 70º
1) Considering that the Sum of the interior angles within a triangle is always 180º
2) We can write the following, and solve for x
x+80 + x +80 +40 = 180
2x +160 +40 = 180
2x + 200 = 180
2x =180-200
2x= -20
x=-10
3) So since angle A = x +80, we can plug it into that the value of x
m∡A = x +80º
m∡A=-10+80
m∡A = 70º

Volume of cone will be ~


Let's find the volume of cone with ~
And as we know, volume of cone is equal to ~
now, let's plug in the values and find the volume ~
Volume of cone is 462 cm³ = 462 ml