OpenStudy (highschoolmom2010):

A hexagonal pencil is a regular hexagonal prism, as shown below. A case edge of the pencil has a length of 4 mm. The pencil (without eraser) has a height of 170 mm. What is the area of the surface of the pencil that gets painted?

4 years ago
OpenStudy (highschoolmom2010):

4 years ago
ganeshie8 (ganeshie8):

first figure out if its LA / SA

4 years ago
OpenStudy (highschoolmom2010):

SA

4 years ago
ganeshie8 (ganeshie8):

why ? we're not painting bases right ?

4 years ago
ganeshie8 (ganeshie8):

look at the picture, yellow color is painted oly on lateral edges.

4 years ago
OpenStudy (highschoolmom2010):

wait it is LA

4 years ago
ganeshie8 (ganeshie8):

yellow color is not there on hexogonal bases

4 years ago
ganeshie8 (ganeshie8):

Yes ! so use LA formula

4 years ago
OpenStudy (highschoolmom2010):

$LA=2\pi rh$

4 years ago
ganeshie8 (ganeshie8):

|dw:1385488873689:dw|

4 years ago
ganeshie8 (ganeshie8):

|dw:1385488938525:dw|

4 years ago
ganeshie8 (ganeshie8):

LA = ph you need to use prism formula ok

4 years ago
OpenStudy (highschoolmom2010):

i cant see drawings

4 years ago
OpenStudy (highschoolmom2010):

oh ok

4 years ago
ganeshie8 (ganeshie8):

oh that sucks. ok 2 pi r h is for cylinder. here u need to use prism formula for LA

4 years ago
ganeshie8 (ganeshie8):

LA = ph p = ?

4 years ago
OpenStudy (highschoolmom2010):

p=(4*170) p=680

4 years ago
ganeshie8 (ganeshie8):

no.

4 years ago
ganeshie8 (ganeshie8):

170mm is the height

4 years ago
ganeshie8 (ganeshie8):

p = 4*6 = 24

4 years ago
OpenStudy (highschoolmom2010):

oh i see lol

4 years ago
ganeshie8 (ganeshie8):

cuz, its a hexogon, there will be 6 sides.

4 years ago
ganeshie8 (ganeshie8):

good, find LA next

4 years ago
OpenStudy (highschoolmom2010):

LA=4080 mm^2

4 years ago
ganeshie8 (ganeshie8):

correct !

4 years ago