Answer:
Explanation:
a.
L
=
329.9
c
m
2
;
S
=
373.9
c
m
2
.
b.
L
=
659.7
c
m
2
;
S
=
483.8
c
m
2
.
c.
L
=
659.7
c
m
2
;
S
=
813.6
c
m
2
.
d.
L
=
329.9
c
m
2
;
S
=
483.8
c
m
2
.
Surface Area of a Cone:
In the three dimensional geometry, a cone is a shape that has a circular base and a lateral surface is associated with a vertex and the base.
The height of the cone is the length of a line segment that joins the base to the vertex of the cone.
The radius of the cone is the same as the radius of the base.
Surface area of a cone
(a) Lateral Surface Area
If
l
and
r
are the slant height and radius of a cone then its lateral surface area is given by the formula-
L
=
π
r
l
where
L
is the lateral surface area of the cone
(b) Total surface area
It is the sum of the area of the circular base and the lateral surface area of the cone.
S
=
L
+
π
r
2
S
=
π
r
l
+
π
r
2
Where
S
is the total surface area of the cone
Answer and Explanation:
Given that the radius and slant height of a right cone is
7
c
m
and
15
c
m
respectively
r
=
7
c
m
l
=
15
c
m
So the lateral surface area of the cone-
L
=
π
r
l
L
=
π
(
7
)
(
15
)
L
=
105
π
L
=
105
(
3.14159
)
L
=
329.866
L
≈
329.9
c
m
2
And the total surface area of the cone-
S
=
L
+
π
r
2
S
=
329.9
+
π
(
7
)
2
S
=
329.9
+
49
(
3.14159
)
S
=
329.9
+
153.937
S
=
483.83
c
m
2
So the lateral area and total area of a right cone are
329.9
c
m
2
and
483.8
c
m
2
respectively.