If the radius of the cone is 6 cm and perpendicular height is 8 cm then find the curved surface area of cone.(take pi=3.14) *
Answers
Answered by
2
Let the perpendicular height and the slant height of the cone be h cm and I cmrespectively
Radius of the base of cone r=8 cm
Curved surface area of the cone =251.2 cm2
∴πrl=251.2 cm2
⇒3.14×8×I=251.2
⇒l=25.12251.2=10
Now,
r2+h2=I2
⇒(8)2+h2=(10)2
⇒64+h2=100
⇒h2=100−64=36
⇒h=36=6 cm
Thus, the slant height and perpendicular height of the cone is 10 cm and 6 cmrespectively.
Answered by
1
Height of the cone is not given
Assuming height of the cone =8m
Let radius of base of cone =r
Curved surface area of cone =188.4cm
2
πrl=188.4cm
2
l=
r
2
+h
2
=
r
2
+8
2
=3.14×r×
r
2
+64
=188.4
=r
r
2
+64
=60
Squaring both sides, we get
r
2
(r
2
+64)=3600
r
4
+64r
2
−3600=0
r
4
+100r
2
−36r
2
−3600=0
(r
2
+100)(r
2
−36)=0
r
2
−36=0
r
2
=36
r=6 m
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