# LESSON6- POLYGONS AND QUADRILATERALS

## LEAD -IN

**Match pictures with words**

**Find words you know.**

### READ ME

**n-gon - n- sides polygon**

**≅ polygons - congruent polygons**

**∼ polygons - similar polygons**

### FALSE FRIENDS

**poligon (wojskowy) - to experimental range or firing ground**

### CHOOSE THE PROPER WORD

**A diagonal of polygon is a segment joining two CONSECUTIVE/NONCONSECUTIVE verices.**

**When all sides of a polygon are equal, the polygon is said to be EQUILTERAL/REGULAR.**

**If two sides of a quadrilateral are both equal and parallel, then that quadrilateral is a PARALLELOGRAM/TRAPEZIUM.**

**In a CONVEX/CONCAVE polygon if any side is lying in the edge of a half -plane, then the other sides all lie in one of the half-planes.**

### FILL IN THE GAPS

**In a ............................... polygon if points A and B both lie in the interior, the segment AB doesn't intersect the
polygon.**

**A rhombus is a parallelogram with two ........................... sides equal.**

**The diagonals of a parallelogram are ............................. unless the parallelogram is a rectangle.**

**A regular polygon is both ....................... and ................................ .**

### LABEL TRUE OR FALSE

**A pentagon can be equiangular without being equilateral.(T/F)**

**Every rectangle is a rhombus.(T/F)**

**A quadrilateral is cyclic if and only if the sums of opposite angles are equal.(T/F)**

**If the diagonals of a quadrilateral bisects each other and are perpendicular to each other, that quadrilateral is a rhombus. (T/F)**

**The bisectors of the angles of circumscribed polygon pass through the centre of a circle. (T/F)**

### Select the phrase that the best completes the sentence:

*must be, cannot be, can be but needn't be*

**A parallelogram inscribed in a circle ............................. a rectangle.**

**The apothem of a regular polygon .............................. longer then the radius.**

**two polygons which have ( for some pairing of vertices) corresponding sides in proportion ................. similar.**

**Two rhombuses .................................similar if one angle of one is equal to some angle in the other.**

**Any two regular polygons with the same number of sides ............................. congruent.**

##
**Classifying Quadrilaterals**

**Classifying quadrilaterals by colouring.**

### TIME FOR PROBLEMS

**Exercise1**

** **

** **

** **

** **

** **

** **

**Listen and solve mathematical problems.**

**Exercise2**

**The area of this rectangle is ……… The perimeter of this figure is ………..**

**Exercise3**

**Each side of a square classroom is 8 m long. The school wants to replace the carpet in the classroom with new carpet that costs 36 zł per square metres. How
much will the new carpet cost?**

**Exercise4**

** **

** **

**Marek likes to fly a kite. He wants to construct a kite in this shape. How many square metres of material will he need to make this kite?**