The Student Room Group
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>

I'm stuck? And am I solving it right? :/



So I drew the diagram below to find the surface area of the prism.
which is
S.A: 2(l x 2x) +2(1/2 x 2x x h) +l x 2x
= 6xl + 2xh

To get h
I calculated the volume which is:
Area of triangle x height

Volume: 1/2 x 2x x h
=xh

so I guess I should make h the subject then substitute it into the surface area equation?? :redface:
Am I right?

ayp.png5.1KB
okau.jpg60.9KB
What paper is this from?
Original post by Adorable98


So I drew the diagram below to find the surface area of the prism.
which is
S.A: 2(l x 2x) +2(1/2 x 2x x h) +l x 2x
= 6xl + 2xh

To get h
I calculated the volume which is:
Area of triangle x height

Volume: 1/2 x 2x x h
=xh

so I guess I should make h the subject then substitute it into the surface area equation?? :redface:
Am I right?



Cut the triangle in half, so the hypotenuse is 2x, the base is x so the height is...
Reply 3
Avatar for Adorable98
Adorable98
OP
15
Original post by zetamcfc
Cut the triangle in half, so the hypotenuse is 2x, the base is x so the height is...


I see, so the height is x therefore the S.A:
2(l x 2x) +2(1/2 x 2x x x) + l x 2x
= 6xl+ 2x2

Now what do I next?:smile:
Original post by Adorable98
I see, so the height is x therefore the S.A:
2(l x 2x) +2(1/2 x 2x x x) + l x 2x
= 6xl+ 2x2

Now what do I next?:smile:


Nope, think Pythagoras, hypotenuse is 2x and the base is x and the height h, so,

(2x)^2 - x^2 = h^2 so what is h.
Reply 5
Avatar for Adorable98
Adorable98
OP
15
Original post by zetamcfc
Nope, think Pythagoras, hypotenuse is 2x and the base is x and the height h, so,

(2x)^2 - x^2 = h^2 so what is h.


Oh yeaah... so
h2= 4x2 - x2
h2= 3x2
h= √3x

Thank you!!:smile:

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you