Find the lateral area, surface area, and volume?

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1 Answer
Jun 18, 2018

Lateral Area: #L.A. = 6pic#
Total surface Area: #A_T = 6pic + 2pic^2#
Total volume: #V_T = pic^2(sqrt(36-c^2))/3 + 2/3pic^3#

Explanation:

The description of the problem is not very clear, but I'll give it a shot, with some assumptions. I will assume that the shape is a right circular cone, inverted, and with a half sphere on top. I will also assume that the #"c"# refers to the radius of the sphere, which is also the radius of the base of the cone, and the #"6"# refers to the slanted height of the cone.

The lateral area of a right circular cone is given by:
#L.A. = pi*r*s#
where #r# is the radius, and #s# is the slanted height
So, here: #L.A. = pi*c*6 = 6pic#

For the total surface area, we need to add the surface area of the half-sphere. The surface area of a whole sphere is given by: #A_s = 4pir^2#, which means that the exposed surface area of our half sphere is #A_h = 1/2*4pic^2=2pic^2#
If we add this to the lateral area, we get the total surface area:
#A_T = 6pic + 2pic^2#

For the volume, let's first figure out the volume of the cone, which is given by: #V_c = pir^2h/3#

From Pythagoras: #h^2+c^2=6^2#
so, #h=sqrt(36-c^2)#

So, the volume of the cone: #V_c = pic^2(sqrt(36-c^2))/3#

The volume of a sphere is #V_s=4/3pir^3#
so, the volume of our half-sphere is: #V_h = 1/2*4/3pic^3=2/3pic^3#

Adding the 2 volumes, we get the total volume of the shape:
#V_T = pic^2(sqrt(36-c^2))/3 + 2/3pic^3#