Area List » area formulas

Is there any site where I can find proofs of various polygon area formulas?

admin — Tue, 27 Dec 2011 07:32:46 +0000

Like triangle, parallelogram etc. It would be good if everything was on the same page

Wikipedia usually explains how the formulae are achieved. I haven’t searched much.

I mean some are obvious: triangle, rectangle/parallelogram, regular penta/hexa/octogon.

How to rewrite area formulas?

admin — Fri, 30 Sep 2011 02:20:38 +0000

So I have no idea how to get the normal formula for area of a triangle (a=1/2xbxh) into a formula so that the missing variable wouldn’t be area, it would be the base. So the formula should start with b= not a=. How do I do this?

a = (1/2)bh
b = a/([1/2]h)
b = 2a/h

Answer: b = 2a/h

Volume, and Surface Area Formulas..Best Answer 10 Points?

admin — Tue, 16 Aug 2011 16:01:55 +0000

I have a math test tommorow. I know this is easy for lots of you, but i’m in grade 8 and i am struggling in math. I need to know the following.

Surface Area of Prisms (ALL)
Surface Area of a Cylinder
Volume of Cylinder
Surface Area of Composite Solids
Volume of Composite Solids

I need the formulas for these. Thanks a million!

The surface area of a prism = 2 × area of base + perimeter of base × H
formula for the surface area of a cylinder is 2*¶r2 + 2¶rh

hope that helps

What is the easiest way to remember formulas for surface area/volume?

admin — Thu, 11 Aug 2011 23:41:46 +0000

I need tips for this, I’ve got an EOG tomorrow!

I figured out a pattern
I put them in this order:

Prism : 2B+Ph
(Prism is the only formula that does not haveπ )

Cylinder: 2πr^2+2πrh
(both sides of the plus sign include 2πr, they just end different)
(Prism and cylinder formulas both end in h)

Pyramid: B+1/2 Pl
(Pyramid is half of a circle therefore yu need to divide by 2)

Cone: πr^2+πrl
(This reminds my of the cylinder formula only it does not include the 2)
(Pyramid and cone both end in slant height)

Sphere: 4πr^2
(I have no trick for this one only the surface area and volume both include a 4 in it)

Volume:

Prism and Cylinder have the same formula: Bh
Pyramid and Cone have the same formula: 1/3 Bh

Sphere is the oddball but again, it is similar to its surface area: V=4/3πr^3

Hope this helps.

Which of these shows how the formulas for the area of a circle and the volume of a cylinder are related?

admin — Wed, 10 Aug 2011 12:09:08 +0000

A)The volume of a cylinder equals the area of its base divided by its height.
B)The volume of a cylinder equals the area of its base multiplied by the radius of the base.
C)The volume of a cylinder equals the area of its base multiplied by the height of the cylinder.

C
when you have doubt,please check the units.
for A the unit is m^2/m=m not correct
for B height is neglegible
God bless you.

How to remeber surface area, lateral area, and volume formulas?

admin — Sun, 07 Aug 2011 21:01:37 +0000

My final exam is coming up and this is but one section of the final. What are some easy or simple ways to think about finding lateral areas, surface areas, and volume? I know the formulas, but what I mean is how would I think about them. For surface area I think of it like finding out the amount of wrapping paper I need to cover an object, something like that. You guys got any good ideas or mnemonics?

you rightly said, surface area is the kind of total area of paper you would need to wrap up the object.

Lateral surface area is the case of a cone remember it like Pie * r * (L)ateral
here lateral is associated with the slant height of the cone.

for volume you could think of the amount of water you would need to fill up the object eg. a cuboid would require l*b*h litre of water to be fully filled.

what are the formulas for surface area and volume of a cube?

admin — Wed, 11 May 2011 08:09:23 +0000

the length, width, and height is 8.

surface area = 6*length^2
volume = length^3

Can you give me 5 facts about Volume and Surface Area formulas?

admin — Sat, 23 Apr 2011 14:21:25 +0000

I need 5. Just little facts.
This is for a math project.
Do not give me the formulas.

Thank you.

i just know one formula
of volume is l^3
and the surface is 6 a^2

volume have 3 sides

What are the formulas for area 4 theses shapes: Parallelogram, Triangle, Rectangle, Square, Trapezoid, Circle?

admin — Sun, 23 Jan 2011 13:45:49 +0000

Thats all.

parallelogram: area=b x h , b=length of base,h=height of perpendicular
triangle: area=1/2 a x b, a=length of base, length of perpendicular
rectangle: area=l x w,l=length ,w=width
square: area=(one side)^2
trapezoid: area=1/2(b1+b2) x h, b1=one base,b2=2nd base,h=height of perpendicular
circle: area=pi r^2 , pi=constant=22/7,r=radius of circle

Can someone answer my math question (arc length, sector area formulas)?

admin — Tue, 02 Nov 2010 17:39:29 +0000

I have a math teacher who doesn’t explain things well so I’m completely lost as to how to do this question:

Assuming that Earth is a sphere of radius 6378 km, what is the difference in the latitudes of Syracuse, New York, and Annapolis, Maryland where Syracuse is 450 km due north of Annapolis? Express your answer in degree-minute-second form.

S= RѲ[2π/360]
[2π/360]—-conversion, rad/deg.
S=450km
R=6378km
Ѳ=S/R
=[ 450/6378][360deg/2π]
=4.042505 deg
= 4 deg.,2 min.,33.02 sec.