Question

The slant height of a cone is 1cm more than the height of the cone.if the radius of the cone is 7cm find the total surface area of the cone

Answer 1

Hey.

Here is the answer.

As, slant height is 1 cm more than the height and radius of the base of the cone is 7 cm.

Let height be x

So, by Pythagoras theorem;

x^2 + 7^2 = (x+1)^2

or, x^2 + 49 = x^2 + 1 + 2x

or, 48 = 2x

so, x = 24 cm

So, slant height,L = 25 cm

As, total surface area of cone = π r L + π r^2

so, total surface area of cone = π×7×25+π×7^2

or, total surface area of cone = 549.77+ 153.94

so, total surface area of cone is 703.71 cm^2.

Thanks.