can u help me solve this?

Question

find the surface area of a cone with a radius of 3in and a slant height of 5in

Answer 1

Do you want the total surface area (TSA) or curved surface area (CSA)? I'll give both:

Given:
r = 3
l = 5

Answer :
CSA = (pi) * r * l
= 15 pi square inches

TSA = (pi)* r (l + r)
= 3 pi * 8
= 24 pi square inches

The curved surface area of the cone is 15 pi square inches and the total surface area of the cone is 24 pi square inches.

Notes:
NEVER approximate the value of pi unless it is asked. I did that and lost marks.

ALWAYS remeber to write the units and the answer as a complete sentence.

Answer 2

Area of surface = area of the base (a circle) + area of skin
area of the base = pi r^2 = pi(3in)^2 = 9 pi in^2
area of the skin = (1/2)hs where s is the length of the circle at the base, circumference = pi(2r) = 2(3in)pi = 6 pi in
area of skin = (1/2)(5in)(6 pi in) = 15 pi in^2
Total Area of surface = Abase + Acircular base
=9 pi in^2 + + 15 pi in^2
= 24 pi in^2

Answer 3

The surface area of a right-angle cone (which is what I assume this is) is given by the formula A = pi*r*S, where S is the slant height. So your surface area is 3.14 x 3 x 5.

Answer 4

the lateralsurface area=pi*r*l=15pi sq.in.
the toatal surface area=pi*3(3+5)
=24 pi sq.in.

Answer 5

Read a math book.