## Sunday, April 22, 2012

### How do we find the Volume of pyramids and cones?

To find the volume of a pyramid  ;
V= (1/3)B*H

Volume of a cone ;
V=(1/3) πr²h  OR V= (1/3)BH

### How do you find the Surface Area and Volume of a sphere?

To find the Surface Area of a sphere you would have to use this formula ;    $\!A = 4\pi r^2.$

To find the Volume of  Sphere you would use this formula ;  $\!V = \frac{4}{3}\pi r^3$

Find the surface area and area ;

## Tuesday, April 10, 2012

### how do we calculate Surface Area of a Cylinder?

To find the Surface Area of a cylinder you would use the formula
S.A.= L.A. + 2B

To find Lateral Area ( L.A.) you would use the formula
L.A.= 2πrh

One you get the lateral area you plug that number into the SA formula. The next step, you would have to find the area base of the base to plug it into the SA formula.
Area of base= πr2

### How do we identify Solids?

Solid Geometry
- Is the 3- dimensional space.
- There is 3 dimensions, width, depth, and height.

Solids of Properties
- Volume
- Surface Area (SA)

Types of Solids
- Polyhedra
- Non - Polyhedra

• Polyhedra: must have flat faces. Some shapes that are considered polyhedra are prisms, pyramids, and platonic solids.

• Non - Polyhedra: Only surfaces that are not flat. Shapes that are non-polyhedra are spheres, cylinders, cone, and torus.

## Sunday, March 25, 2012

### How do we find the area of a circle?

To find the area of a circle you would use the formula :

A =πr2
A is the area
r is the radius of the circle

WIth the given information you plug in the number(s) to the formula.

### How do we find the area of regular polygons?

To calculate the area of a regular polygon you would use the formula :
A = ½ * nas        OR       A= ½ * Pa

A is the area
P is the perimeter
a is the apothem
s is the length of each side
n is the number of sides

## Thursday, March 22, 2012

### how do we find the area of parallelograms, kites, and trapezoids?

When solving the area to a figure like parallelograms, kites,and trapezoids, each one of those shapes has their own formula.

Area of a Parallelogram:

Area of a Kite:

Area of a Trapezoid:

Example #1

Parallelogram Area = B x H
Area = 12  x 5
Area =  60 cm ²

Example #2

Kite Area =  ½ d1d2
Area= ½ ( 8 x 6)
Area= ½  (48)
Area = 24 cm ²

Example #3

Trapezoid Area = ½ h( b1 +b2 )
Area =  ½ 5(10 + 14)
Area  =  ½ (120)
Area  = 60in²