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Tuesday, December 16, 2014

Circle and Secant Segment Problems, 2

Category: Plane Geometry

"Published in Newark, California, USA"

From the given figure, find the ratio x : y.

Photo by Math Principles in Everyday Life

Solution:

Consider the given figure above

Photo by Math Principles in Everyday Life

The given figure consists of two secant segments that are drawn in a circle from an external point. In the same figure, there are two chords that intersect inside a circle. In this case, we can solve for the values of x and y by using the two theorems. 

If the first theorem says "The measure of an angle formed by two chord that intersect inside a circle is equal to the half the sum of the measures of the intercepted arcs.", then the working equation is



If the second theorem says "The measure of an angle formed by two secants, two tangents, or a secant and a tangent drawn from a point outside a circle is equal to half the difference of the measures of the intercepted arcs.", then the working equation is



From the two working equations, if we add the two equations, y will be eliminated. The value of x is


---------------------


Substitute the value of x to either one of the working equations, we have


 


Therefore, the ratio of x and y is


 

Monday, December 15, 2014

Square, Rectangle, and Parallelogram Problems, 13

Category: Plane Geometry, Trigonometry

"Published in Newark, California, USA"

From the given figure, find A + B C. 

Photo by Math Principles in Everyday Life

Solution:

Consider the given figure above

Photo by Math Principles in Everyday Life

Since the given figure is a rectangle that consists of three squares, then we can solve for the values of A, B, and C by using basic trigonometric functions. The given diagonals are the hypotenuses of a square and two rectangles, respectively. 

The value of C is
 
 
 
 

The value of B is
 
 

 
 

The value of A is
 
 
 
 
 

Therefore,
 
 

Sunday, December 14, 2014

Solving Trigonometric Equations, 10

Category: Trigonometry

"Published in Vacaville, California, USA"

Solve for the value of x for the equation:


Solution:

Consider the given equation above


Since there's a half-angle function in the given equation, then we need to convert it into single angle function first as follows







Take the inverse cosine on both sides of the equation, we have 



                                     or

Therefore, the values of x are


 
where n is the number of revolutions.