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>

I'll do part (a) to get you started.
The angle 'a' pairs up with the 123 degree angle as a corresponding angle pair. Due to the parallel lines, the corresponding angles are congruent. Therefore a = 123.
We also see that b = 123 as well since a = b (they are vertical angles).
Notice how angle c is adjacent to the 123 degree angle. These two angles form a straight line, so they must add to 180 degrees.
c+123 = 180
c = 180-123
c = 57
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To summarize, we have these three angles
a = 123
b = 123
c = 57
Answer: 38 cm
Step-by-step explanation:
3 = 48 divided by 16
Mark brainliest please
Hope this helps you