Sunday, May 6, 2012

Aim: How do we use scant, chord and tangent ratios in cirles?

-If Two cords intersect inside a circle, then the prodect of the segements of one cord equals the product of the segements of the other chord.

-Theorem 84: If two secant segements intersect outside a circle, then the product of the secant segements with its external portion.
WO=WO

How do you find the surface area and volume of a sphere?

Aim: How do you find the surface area and volume of a sphere?

SPHERES
- A sphere is the set of all points in the space equidistant from given point called the center.


Formulas:
SA= 4(3.14r^2)
LA= 4(3.14r^2)

For Example:
1. find the Surface area of the Sphere
r=17
formula=4(3.14r^2)

Step 1: write the formula if you want
EX: formula=4(3.14r^2)Step 2: Plug in the given information into the formula
EX: SA=4(3.14r^2) R=17
SA:4(3.14*17^2)
Step 3: Solve the problems
EX: 4(3.14x17^2)
        4(3.14x289)
        4(907.9)
      SA=3631.6
Try on your own:
Solve for SA


R=13

How do we find the surface area and lateral area of pyramids and cones?

Aim: How do we find surface area and lateral area of pyramids and cones?
Do Now: Reviewing Triangles
1. Find the area of the triangle
height is 20 and the base is 16



Pyramid
A pyramid is a solid that connect a polygon base to point. The Pyramid has 3 triangle faces and a base that is a square.

The Slant Height of a pyramid is the height of one of the lateral faces.

* Formulas*
Lateral area= (1/2)pl
SA= L.A+B

Solve for lateral area and surface area

Saturday, May 5, 2012

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

Aim: How do we find the area of parallelograms, kites and trapezoids?

Area of a Trapezoid is the 1st base + the 2nd base and then you divide by 2 and then times the height given in the trapezoid.
Formula: b1+b2/2*H 

Try it out:
1.  Base 1=14
Base 2=12
The Height=6






Area of a Kite is the first diagonal times the 2nd diagonol divided by 2.
Formula: d1*d2/2

Try it:
1. Diagonal 1=7
Diagonal 2= 16




How do we calculate the area of rectangles and triangles ?

Aim: How do we calculate the area of rectangles and triangles ?

Triangle Area Conjecture= (1/2)bh
The Area of a triangle is given by the formula A=(1/2)bh. A is the Area, B is the length of the base, and H is the height of the triangle.

Example:

 The Triangle ABC.
The Length of AC is 9mm and the length of AB is 20mm.

Step1: Know the given information, The problem gave you already that the length of the base is 9mm and also that the height is 20mm.

Step2: plug the new information in the formula A=(1/2)bh 
Ex: A=(1/2) 9 X 20

Step 3: Multiply The base and the height
Ex: 9 X 20= 180

Step4: Once you got your answer divide the answer by 2
180/2= 90

And the answer to the problem above is 90mm^2

Sunday, April 22, 2012

The Elegant Locus

 Aim: The Elegant Locus


Definition: The locus is the set of all points that satisfy a given condition.


- A locus is a general graph of given equation.


- The locus of points equidistant from a single point is set of point, equidistant from the point, in every direction.


- The locus of points equidistant from a single point is a set of points, equidistant from the point, in every direction.

- The Locus of points equidistant from two points is perpendicular bisector of the line segment connecting the two points.

- The locus of points equidistant from a line are two lines, on opposite sides, equidistant and parallel to that line.

- The locus of points equidistant from two parallel lines is another line, half way between both lines, and parallel to each of them.

-The locus of points equidistant from two intersecting lines are two additional lines that bisect the angles fromed by the original lines.

Try now: From Regentsprep.org






The locus of points equidistant from two intersecting lines is ...
Choose:
one circle two parallel lines
two circles a pair of angle bisectors

Sunday, April 15, 2012

Aim: How do we identify solids ?

Aim: How do we identify solids ?

    Solid Geometry: Solid geometry is the geometry of 3-dimensional space.
Properties:
  • Volume
  • Surface Area
Two Main types of solid:
  1. Polyhedra
  2. Non-Polyhedra
Polyhedra: Flat Surface
  • Prism                       
  • Pyramids
  • Platonic solids
Non-Polyhedra: If any surface is not flat
  • Sphere
  • Torus
  • Cylinder
  • Cone
Prisms: Has the same cross section all along its length
Cross sections: The shape you get when you cut straight down
Surface Area: The area of the bases + the Lateral Area ( area of the side)