GEOMETRY

NOTES OF ART

IMPORTANT DEFINITONS ABOUT CIRCLES 

Circle: set of points at the same distance to a point called 'centre'.

Circunference:  it's the full lenght of a circle. 

Centre: it's a point equidistant to any point on a circle. 

Radius: it's a length of a line segment from the centre to its perimeter. 

Diameter: a line segment that pases though  the centre and conects two points of a circle. Its length is double the radius. 

Chord: line segment which conects two points of  the circle not through the centre. 

Arc: segment of a circle. 

Arrow: its a line segment centre chord and pass to the centre. 

IMPORTANT DEFINITONS ABOUT ANGLES  AND LINES 

Parallels: they are two lines which never intersect them selves so all their points are equidistant. 

Perpendicular: they are  line with meat forming four right angles. 

Oblicue: they are  line which are not parallels neither perpendicular. 

ANGLES : it's a figure formed by two rafs sharing a common endpoint ( vertex ).

● Types of angles (position )

Complementari angles: they are couples of angles which sum is 90°.

Suplementary angles: they are couples of angles which sum is 180°.

● Types of angles (form).

They can be: right, obtuse, acute, flat, complement, cero.

The angle bisector: when I drive an angle into two equals parts. 

OPERATIONS WITH ANGLES 

-Adition:

-Subtraction:

-Multiply:

-Divide a right angle in 3 parts equals:

POLYGONS 

Star poligons: its a particular polygon case whith a star shape, created out of linking together non consecutive of a regular polygon.  

Inscribed polygon: they are polygons placed inside circles so all the vertex of the polygon are placed on the circle. 

Convex polygon: any line draw through the polygon meets its boundary exctly twice. 

 Non-convex (concave): a line maybe found which meets its boundary more more than twice.  

TRIANGLES: it's a flat with 3 sides and 3 angles. 

Construction an equilateral triangle when I know 1 side 

Construction an equilateral triangle when I know the radius:

Construction an isosceles triangle when I know 2 sides:

Made a right triangle when I know 2 sides:

Made a right triangle when I know 1 sides and the apotem:

 Do the triangle when I know three sides:

QUADRILATERAL

 They are polygons with 4 sides and four angles. 

● Paralellograms

 They are quadrilaterals with 2 sides of parallel opposite equal sides and 2 pairs opposite equal angles. 

● Non-parallelograms or trapezium

Only one pair of sides are parallels.