Question

If radius of the base of a cone is 140dm and its slant height is 9m. Find the
(i)curved surface area
(ii)total surface area ​​

Answer 1

Answer:

We know that the total surface area S of a right circular cylinder of radius r and slant height l is given by

S=πr

2

+πrl=πr(r+l)

Here, r=12mandl=9m

∴S={

7

22

×12×(12+9)}

2

=792m

2

Answer 2

Question= If radius of the base of a cone is 140dm and its slant height is 9m. Find the

(i)curved surface area

(ii)total surface area

Solution⬇️

Height =24cm

radius =14÷2=7cm

slant height=L=?

L2=R2+H2

L2=72 +242

L2=49+576

L2=625

L=25

VOLUME=1÷3×22÷7×7×24

VOLUME=1232CM

CURVED SURFACE AREA =22÷7×7×25

CURVED SURFACE AREA =550

TOTAL SURFACE AREA=22÷7×7×25+7

TOTAL SURFACE AREA =704CM