Area List

The surface area of a cone is A = πrl where l is the slant height of the cone (if you don’t know it, but know the height and radius, you can use the Pythagorean Theorem).

You can find the proof here:
http://www.allendesigns.com/AreaofCone/AreaofCone.htm

For a cylinder, the surface area is:

A = 2πr² + 2πrh

For the cylinder, we compute the area of the top and bottom (which are just two congruent circles), plus the lateral area (which is just a rectangle with it’s height being the height of the cylinder and the width being the perimeter of either base).

I hope this helps!

Which formulas can be used to find the surface area of a right prism where p is the perimeter of the base, h is the height of the prism, BA is the area of bases, & LA is the lateral area?
there may be more than one right answer.

A. SA = BA + 1/2 ph
B. SA = BA + 1/2 LA
C. SA = BA + LA
D. SA = BA + ph
E. SA = BA – LA

c

PLEASE HELP! Very important help much appreciated

Hi,

Lateral Area of any prism = perimeter of base x height of prism

Lateral Area of any regular pyramid = ½ x perimeter of base x slant height of pyramid

(Remember: apothem² + height² = slant height²)

Lateral Area of any cone = πrs, where r = radius of base and s = slant height

(Remember: radius² + height² = slant height²)

Lateral Area of any cylinder = 2πrh, where r = radius of base and h = height

I hope that helps!!

I need to get a better approach towards getting the answer to these types of questions:
~Find the height of a pyramid whose base is a regular nonagon with side length 8 inches and lateral faces are isosceles triangles with legs 30.
~ how do you get the answer to this question..step by step?

volume:
triangle-base x height divide by 2
pyramid-i don’t know but u cant blame me im only in 6th grade
cone -i dont know either but im the only one who answer the question so far because i luv math
cylinder-i know this lol………..ummm……yeah pie x radius squared x height

vote me best answer please !!!!!!!!!!!!!
LuBbBsz NaUtIi240 xoxoxox

Volume and area formulas?! help?!?
SURFACE AREA

rectangular prism_______________________
triangular prism______________________
cylinder___________________________
square pyramid____________________
cone______________________________
sphere____________________________

VOLUME

rectangular prism____________________
triangular prism_____________________
cylinder_____________________________
square pyramid______________________
cone________________________________
sphere___________________________

formulas 2-d object

area of a square_____________
rectangle______________
parallelogram_____________________
trapezoid____________________
rhombus_______________________
triangle_________________________
circle___________________________
circumference of a circle

THANKS SO MUCH! I REALLY REALLY APPRECIATE!

2-D
Square= Length x Width
Rectangle= Length x Width
Parallelogram= Base x Height
Trapezoid= Base x Height
Rhombus= Base x Height
Triangle= Base x Height /2
Circle= Pi R^2
Circumference= Pi x diameter Or… 2 x Pi x radius

http://img410.imageshack.us/img410/5233/mathsl.jpg

I just sketched 3 shapes quickly. Im very unsure what formula to use on A and C.

Thanks

A & B:- This figure is formed by 2 right angled triangles and 3 paralellograms
C :- Formed by 4 paralellograms and 2 trapeziums
Formulas:
Area of paralellogram = base * height
Area of triangle = (1/2) * base * height
Ares of trapezium = (1/2) * height * (sum of lengths of its parallel sides)

NOTE : If you need the solution for this question, please let me know

I need help with these formulas:

What is the formula to finding the area of a circle if all you have to work with is the diameter.

What is the formula to finding the cirfumference of a circle is you only have the radis or diameter?

Please help me, I am confused!!!

2 times radius = diameter d=2r, r=d/2
If you have the diameter divide it by 2, to get r, the radius.
Area = pi r^2
Circumference = pi x diameter

The area of a regular pentagon is equal to 1.720a (where a= the length of a side), so multiply that by length for volume of a regular prism, or for area, multiply it by 2 and add (5 times [a * L]), where L is the length.

In the case of an irregular pentagonal prism, divide one end into 5 triangles, find the area of each, & add them together, then follow the same steps as above.

I have a perimeter and area test on Wednesday and I need to memorize the formulas for these shapes:

Rectangle:
Perimeter: (Base + Height) x 2
Area: Base x Height

Square:
Perimeter: side x 4
Area: side x side

Triangle:
Perimeter: Add 3 sides
Area: 1/2 x base x height

Parallelogram:
Perimeter: (Base + Slant Height) x 2
Area: Base x Height

Circle:
Perimeter: pi x diameter
Area: pi x radius squared

Rhombus
Perimeter: side x 4
Area: side x side

Irregular Shape:
Perimeter: Add all sides
Area: Divide into sections
Apply the apporate formula
Add together
I’m in grade 7 and these are the right formulas my teacher gave them to me.

There is nothing else you need to do but actually remember what the formulas are. Good luck in your exam.

I’m to lazy to find them myself, Bwahahaha!
What’s base?

V = Area of base * Height
= π r² h

SA = 2 π r h + 2 π r²

Area of the base, if your talking about a circular cylinder is a circle (area = π r², where r = radius of circle) if you’re looking at a square cylinder (area = s², where s is length of one of the sides), if a cylinder with base of a rectangle (Area of the base = lw), if a cylinder with a base of a triangle (Area of base = 1/2 bh) etc.

The formulas I gave, assume a cylinder with a circular base.