Question

a cubical block of side 7cm is surmounted by a hemisphere. what is the greatest diameter the hemisphere can have? find surface area of the solid.
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Answer 1

Step-by-step explanation:

The greatest diameter=side of the cube=7cm.

The radius of the hemisphere =3.5cm.

Now,

The Surface Area of Solid=Surface Area of Cube - Surface Area of Base Hemisphere + Curve Surface Area of Hemisphere

Surface Area of Cube

=6×side

2

=6×7×7

=294sq cm

Surface Area of Base of Hemisphere is,

=πr

2

=

7

22

×3.5

2

=38.5cm

2

Curved Surface Area of Hemisphere is,

=2×38.5

=77sq cm

∴ total Surface Area is =294−38.5+77

=332.5sq cm.

Answer 2

Answer:

We have,

Side of cubical block=7cm.

Then radius of hemisphere =

2

7

cm=3.5cm.

Then,

Total surface area of the solid=Total surface area of cube-Area of base of hemisphere +curved surface area of hemisphere.

⇒TSA=6×7

2

−π×(3.5)

2

+2π(3.5)

2

⇒TSA=332.465cm

2

.

Hence, this is the answer.