Question

Someone please help with surface area of pyramids and cones

Answer 1

are these answers correct?
the first one i got 282.6m^2
the second one i got 175.84in^2

Answer 2

if you can cut the cone up its lengthand make into part of a circle, the surface area is easy to get :) maybe even easy if I think about it some

Answer 3

is the 10 inches the length up the side of the cone or the height?

Answer 4

length

Answer 5

its actually slant height

Answer 6

then that 10 inch length is the radius of a larger circle, find its circumference"

2pi10 20pi is its curcumference

the small base circle is the length of the circumference that you want to find an area for

2pi4 = 8pi

make sense?

Answer 7

kinda

Answer 8

\[s =\pi \times r ^{2}+\pi \times r \times l\] is the formula i need to use

Answer 9

length of an arc = theta(r)

8pi = theta(10)

theta = 8pi/10 = 4pi/5

area of sector = theta r^2/2

(4pi/5)(10)(10)/2

200/5 = 40pi fpr the surface area of the cone, do we include that base in this or not?

Answer 10

40pi + 16pi = 56pi if I did it right :)

Answer 11

ok

Answer 12

would = 175.84in^2

Answer 13

175.92 is what I get... is that close enough?

Answer 14

175.84 if you use (3.14)

Answer 15

yea

Answer 16

how would i find the surface area of this one

Answer 17

if im doing it right, I get 85pi

Answer 18

would i use half the diameter?

Answer 19

if you dont have answers to check against, I would suggest gettting a second opinion :)

but yes, radius is half the diameter

Answer 20

\[s =\pi \times 5^{2}+\pi \times 5 \times 12\]

Answer 21

i got 25pi + 60pi too :)

Answer 22

im glad the formula works :)

Answer 23

witch would = 266.9ft^2

Answer 24

would you please help me with three more

Answer 25

i could try.... getting kinda deer in the headlights feeling....must.....carry.........on. . . . . . . ok

Answer 26

find the surface area of the regular pyramid

Answer 27

#31 3cm is pointing to what?

Answer 28

3cm is height i believe

Answer 29

is it face height or pyramid height?

Answer 30

the formula for this on is S=B+1/2Pl

Answer 31

looks like pyramid hight

Answer 32

pyramid height would have a dotted line stricking down the middle of it..... i think its face height.

Answer 33

so do i

Answer 34

4cm^2 + 12 cm^2 = 16 cm^2 for #31

Answer 35

#32...all I see is a 7 and not much else for details...

Answer 36

thats all there is

Answer 37

is that all sides are 7? like an equalateral triangle?

Answer 38

yea

Answer 39

then I would do:

4 times (1/2)(49)sin(60)

84.87 m^2

Answer 40

if you have a side-angle-side, the area can be determined by:

(side)(side)(sin(angle))/2 and there are 4 sides so I timesed it by 4 :)

Answer 41

(side)sin(a) = height, and the other side = base

Answer 42

ok

Answer 43

and for the last one its just like the first except with decimals..

Answer 44

(9.2)^2 + 4(9.2)(13)/2

Answer 45

84.64 + 239.2 = 323.84

Answer 46

okay thank you so much

Answer 47

youre welcome :)