Answer:
<h2>A) 3 cm</h2>
Step-by-step explanation:
The formula of a volume of a cylinder:

r - radius
H - height
We have r = 1cm and H = 21cm. Substitute:

The formula of a cone:

r - radius
H - height
We have V = 21π cm³ and H = 7cm. Substitute:
<em>divide both sides by π</em>
<em>divide both sides by 7</em>
<em>multiply both sides by 3</em>

Answer:
X=7
Hope it was helpful
Step-by-step explanation:
Good luck ^___^
Dont cheat do it your self
Answer:
the answer is D.
Step-by-step explanation:
multiply each row in the first matrix by each column in the second matrix.
[4*-2+2*7 4*5+2*-1]
simplify each element of the matrix by multiplying out all the expressions.
[6 18]
this matrix is already in the most simplified form.
[6 18]