Question

Find the lateral area of a cone with a radius of 7 ft. and a slant height of 13 ft. Use 3.14 for π and round to the nearest tenth.
439.6 ft2
324.5 ft2
571.5 ft2
285.7 ft2

Find the surface area of a square pyramid with a base length of 24 cm and a height of 16 cm.
1056 cm2
1536 cm2
816 cm2
1344 cm2

Answer 1

No, sorry. ☺

Answer 2

do you know the formula for pt1?

Answer 3

nope, the first question. do you know the formula?

Answer 4

hmm. you should refer to your textbook first.

Answer 5

One second I just need remember what lateral means lol

Answer 6

lol thanks the other person didnt even really try to help me :/

Answer 7

http://www.mathwarehouse.com/solid-geometry/cone/images/surface-area-of-cone/lateral-surface-area-formula-picture.jpg

It's the area of the cone, not including the area of the base.

Answer 8

Well from what I understand about the problem it seems like you need to find the height first, since you only have the slant height and the radius of the cone

Answer 9

\[LA = \pi r h _{s}\] where r = 7 ft and hs = 13 ft

Answer 10

But if you picture it then we can say see that the radius, slant height, and actual height make a right triangle

Answer 11

soo what do i do with the 13?

Answer 12

I just showed you... \[\large LA=πrh _{s} \]
where r = 7 ft and hs = 13 ft and LA is lateral area.

Answer 13

Oh lol lateral area lol, yeah you can use the formula

Answer 14

For some reason I was thinking you needed the actual height of the cone to be able to do this

Answer 15

is the answer d

Answer 16

You can do it that way too, using pythag to find the actual height.

Answer 17

from the formula, LA = 285.74 ft^2

Answer 18

ya thats what i got

Answer 19

is that right?

Answer 20

Sorry im like doing 4 things at once so I can't really calculate it right now but I mean if you follow the formula and calculate it right then it should be right

Answer 21

ok so the second question is the formula the same?

Answer 22

I think for the second one you need to use the pythagorean theorem to find the slant height

Answer 23

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Answer 24

Well to find surface area all you need to do is find the area of the sides of the figure right? so we notice for the square pyramid that the sides of the pyramid are triangles thus all we need to find the area of that is the 1/2 times the base times the height for each triangle....then we notice the bottom is a square so we just need the length times the width