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

Adorable98
Badges: 15
#1
Report Thread starter 3 years ago
#1


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??
Am I right?

Attached files
0
reply
username1969391
Badges: 14
Rep:
?
#2
Report 3 years ago
#2
What paper is this from?
0
reply
zetamcfc
Badges: 18
Rep:
?
#3
Report 3 years ago
#3
(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 2xx h
=xh

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

Cut the triangle in half, so the hypotenuse is 2x, the base is x so the height is...
0
reply
Adorable98
Badges: 15
#4
Report Thread starter 3 years ago
#4
(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 2xx x) + l x 2x
= 6xl+ 2x2

Now what do I next?
0
reply
zetamcfc
Badges: 18
Rep:
?
#5
Report 3 years ago
#5
(Original post by Adorable98)
I see, so the height is x therefore the S.A:
2(l x 2x) +2(1/2 x 2xx x) + l x 2x
= 6xl+ 2x2

Now what do I next?
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.
1
reply
Adorable98
Badges: 15
#6
Report Thread starter 3 years ago
#6
(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!!
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts

All the exam results help you need

2,419

people online now

225,530

students helped last year

University open days

  • University of Dundee
    Undergraduate Open Day Undergraduate
    Mon, 26 Aug '19
  • University of Aberdeen
    General Open Day Undergraduate
    Tue, 27 Aug '19
  • Norwich University of the Arts
    Postgraduate (MA) Open Day Postgraduate
    Sat, 31 Aug '19

How are you feeling about GCSE Results Day?

Hopeful (208)
12.78%
Excited (144)
8.85%
Worried (295)
18.12%
Terrified (367)
22.54%
Meh (149)
9.15%
Confused (35)
2.15%
Putting on a brave face (223)
13.7%
Impatient (207)
12.71%

Watched Threads

View All