Question

Find the area of curved surface of the circular cone.
given
(i) Perimeter of the base 88 cm, slant height 2 dm
(ii) Area of the base 154 cm², height 24 cm​

Answer 1

WKT

2πr = 88 cm

so r = 88/2π

l = 2 dm = 20 cm

πr² = 154 cm²

h= 24 cm

CSA of cone = πrl

= π x 88/2π x 20

= (π x 88 x 20)/2π

= 88 x 10

= 880 cm²

Answer 2

Step-by-step explanation:

Let the radius of the base of the cone be r cm

Now circumference of base =154cm

2πr=154

r=154×7 49

-------- = -----

22×2 2 cm

Slant height =7cm

Curved area of cone =πrl= 7cm×22 × 49×7=539

cm2 ------

2