Question

perpendicular height of a cone is 12 cm and its slant height is 30 cm find the radius of base of the cone​

Answer 1

Answer:

The radius is r=5 cm

Step-by-step explanation:

Given perpendicular height of a cone is 12 cm and its slant height is 13 cm. we have to find the radius of base of cone.

By Pythagoras theorem

AC^2=AB^2+BC^2AC

2

=AB

2

+BC

2

⇒ l^2=h^2+r^2l

2

=h

2

+r

2

⇒ 13^2=12^2+r^213

2

=12

2

+r

2

⇒ 169=144+r^2169=144+r

2

⇒ r^2=169-144=25r

2

=169−144=25

The radius is r=5 cm

Answer 2

Step-by-step explanation:

Given that, height of cone = 12 cm and slant height of cone = 13 cm.

We need to find radius of the base of the cone, r.

In right-angled ∆AOB, using Pythagoras theorem,

AB2 = AO2 + OB2

⇒ OB2 = AB2 – AO2

⇒ r2 = 132 – 122

⇒ r2 = 169 – 144 = 25

⇒ r = √25

⇒ r = 5

Thus, radius of the base of the cone is 5 cm.

.