Since we are already given the formula and all the information, the only thing that we have to do is input all the values and simplify until we get an answer. In addition, we must also note that the radius is 4 (because the diameter is equal to twice the radius, meaning that if the diameter is 8, the radius is 4). Using the formula and information given, we get:
Volume = 3 * (4)² * 12
Which simplifies to:
Volume = 3 * 16 * 12
Volume = 576
Now, we need to know the units. Since this is a 3d shape, and the unit for the lengths of the sides are centimeters, this answer will be in centimeters cubed. That means our answer is 576 centimeters cubed.
an = a1r^(n-1)
a5 = a1 r^(5-1)
-6 =a1 r^4
a2 = a1 r^(2-1)
-48 = a1 r
divide
-6 =a1 r^4
---------------- yields 1/8 = r^3 take the cube root or each side
-48 = a1 r 1/2 = r
an = a1r^(n-1)
an = a1 (1/2)^ (n-1)
-48 = a1 (1/2) ^1
divide by 1/2
-96 = a1
an = -96 (1/2)^ (n-1)
the sum
Sn = a1[(r^n - 1/(r - 1)]
S18 = -96 [( (1/2) ^17 -1/ (1/2 -1)]
=-96 [ (1/2) ^ 17 -1 /-1/2]
= 192 * [-131071/131072]
approximately -192
THE SECOND ONE IS THE CORRECT ANSWER (B)
good luck
Polyhedron, by definition, is formed by intersecting planes, so each part of its surface is either a vertex or an edge, or a flat piece of a plane.
Explanation:
The definition of polyhedron implies that each side is a piece of a flat surface.
