glory twinkle
DESCRIPTION
Presented by : Anggun Nugraha Oktaviani Deti Nur Karina Fiona Salfadilla Rifda Nadifah Umroh Indah LestariTRANSCRIPT
GLORY TWINKLE IX E
Anggun Nugraha OktavianiDeti Nur KarinaFiona SalfadillaRifda Nadifah
Umroh Indah Lestari
CONE
CONE
The
defi
nitio
n
The
elem
ents
The net The examples in daily life
The form
ulas
The exam
ple of
question
CONE
In geometry, the cone is a special pyramidbased circle. Cone has 2 sides, 1 angle point
and 1 edge. Side of the upright cone is not a triangle but in the form of curved cone called a curved surface or lateral area.A cone consist of the base circle shaped and the
blanket sector shaped.
The Elements of Cone
h
r
ll
r
2 ∏r
2 ∏ lC=2 ∏ rC=
Area of Circle∏ l 2
2rB=∏
B = Base area of circleC = Circumference of circleh = height of coner = radius of circlel = slant height of cone
The Net of Cone
The example of cones in daily life
CONES
TRAFFIC CONE
ANAK KRAKATAU MOUNTAIN
The Formula of Cone Lateral Area / Curved Surface :
=area of sectorarea of circle
Perimeter of sector / perimeter of cone’s base perimeter of circle
=area of sector
∏ l 2
2 r∏
2∏ l 2
r=
area of sector∏ l 2 l
∏ l 2
∏ l 2
∏ r lArea of sector =
h
r
ll
r
2 ∏r
2 ∏ lC=2 ∏ rC=
Area of Circle∏ l 2
2rB=∏
Total Surface Area :T = Area of sector + Area of cone’s baseT = Cs + BaT = (∏ r l) + (∏ r2 )
Volume Of Cone :
V = Ba . h
V = (∏ r2 ) h
Example
h = 12cm
r = 5cm
A cone has a base diameter of 10 cm and height of 12 cm. For ∏ = 3.14Find : a. the curved surface area b. the base area c. the surface area d. the volume
SolutionGiven that : r = 5 cm
h = 12 cm
∏ = 3. 14
l 2 = h2 + r 2
l = l = l =
l = l = 13 cm
So, the slant height of cone is 13 cm.
a. The curved surface area :Cs = ∏ r l = 3.14 x 5 cm x 13 cm = 204.1 cm2
So, the curved surface area of cone is 204.1 cm 2
b. The base area : Ba = ∏r 2
= 3.14 x 5 cm x 5 cm = 78.5 cm 2 So, the base area of cone is 78.5 cm 2
c. the surface area = ?
the surface area = Cs + Ba = 204.1 cm2 + 78.5 cm2 = 285.6 cm2
so, the surface area of cone is 285.6 cm2
d. volume = Ba . h
= 78.5 cm2 x 12 cm
= 314 cm3
So, the volume of cone is 314 cm3
EXERCISE
Given that the curved surface of cone beside is 550 cm2 and the radius is 7 cm
Find : a.The slant heightb.The surface area of the
conec.The height of cone
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Presented by :Anggun Nugraha Oktaviani
Deti Nur KarinaFiona SalfadillaRifda Nadifah
Umroh Indah Lestari
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