geometry

Triangles, Polygons and Quadrilaterals

Triangles

• isosceles, equilateral

• acute-triangle, right-angled triangle, obtuse triangle

• the sum of the interior angles is 180°

• theorem of Pythagoras

• altitude, area

•  $T=\frac{a\times m_a}{2}$  

Multiple Choice

In a triangle there are equal angles opposite equal sides.

• true

• false

• not always true

Multiple Choice

In any triangle is a shorter interior angle opposite the longer side of two sides than opposite the shorter one

• true

• false

• depends on

Multiple Choice

The set of points of the plane which are equidistant from points A and B is called the.......of the line segment A and B.

• straigth line

• angle

• perpedicular bisector

• I have no idea

Circle

• The set of points of the plane which are at a given point O of the plane is a circle

• center, radius, diameter, chord, secant line, tangent line

Multiple Choice

The area of (a polygon)

• kerület

• terület

• felszín

• térfogat

Multiple Choice

The perimeter (of a polygon )

• kerület

• terület

• felszín

• térfogat

The inscribed circle of a triangle

- the intersect point of the three interior angle bisectors

- equidistant from all sides

- A=r×s

s=half of the perimeter

Calculate the area of the triangle if P=17 m and r=2.5 cm

The circumscribed circle of a triangle

• the intersect points of the three perpendicular bisectors of the sides

• equidistant from all vertices

Polygons

• convex, concave

• numbers of diagonals 

   $\frac{n\left(n-3\right)}{2}$  

• the sum of interior angles  $\left(n-2\right)\times180°$  

• one interior angle of a regular polygon  $\frac{\left(n-2\right)\times180°}{n}$  

• the sum of the exterior angles 360°

Quadrilaterals

• the sum of interior angles 360°

• trapezium

• paralellogram

• rhombus

• kites

• rectangle

• square