help me wit these 3 questions plz.
A cone has a base radius of 7 centimeters and a height of 21 centimeters.
What is the volume of the cone?
A.
28 π cm3
B.
49 π cm3
C.
147 π cm3
D.
343 π cm3
Answer (2)
Cone
r = 7 c m h = 21 c m
V = 3 π ∗ r 2 ∗ h = 3 π ∗ 7 2 ∗ 21 = 7 2 ∗ 7 ∗ π = 7 3 π = 343 π c m 3
Answer: D
Cylinder
r = 5 f t h = 16 f t
V = π ∗ r 2 ∗ h = π ∗ 5 2 ∗ 16 = 25 ∗ 16 π = 400 π f t 3
Answer: A
3.Pyramid
In this case it will be
V = 3 a ∗ b ∗ h
a = 9 f t b = 4 f t h = 12 f t
V = 3 4 ∗ 9 ∗ 12 = 4 ∗ 3 ∗ 12 = 144 f t 3
Answer: B
The volume of the cone with a base radius of 7 cm and a height of 21 cm is calculated using the formula V = 3 π r 2 h , resulting in a final volume of 343 π cm 3 . The correct answer is option D.
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