Page 188 - ICSE Math 8
P. 188

2.  In the trapezium MUST given alongside, TS || MU. The perimeter of the trapezium is 48 cm. If one of
                        the parallel sides is twice the other and the sum of the two non-parallel sides is 21 cm, find the lengths
                        of two parallel sides.
                                                                                          E
                      3.  In the kite SIDE given alongside, diagonals SD and EI intersect
                         at point O. Give reasons for the following:               S
                         (a)  ES = ED                     (b)  IS = ID                    O     D         N
                         (c)  ∠EDI = ∠ESI                 (d)  ∠DEO = ∠SEO                          3x – 5    22
                      4.  In the kite TURN in which diagonals TR and NU intersect at a
                        point. Find the value of x and y.                                 I       T        O      R
                      5.  In the given trapeziums, find the value of x and y.

                        (a)  K         x  C          (b)     B              E                       33        7y – 2
                               130°                            110°       y

                                                                                                         U
                               y      90°                 x                   50°
                            P             I           R                            A


                                                              AT A GLANCE
                    ¾   A plane curve is formed when a number of points are joined on a plane without any break.
                    ¾   A convex polygon is a simple polygon where each interior angle is less than 180° and the segment
                        connecting  any  two  points  in  the  interior  of  the  polygon  is  wholly  contained  in  the  interior  of  the
                        polygon.
                    ¾   A concave polygon is a polygon which has at least one interior angle greater than 180° and it is always
                        possible to locate two points in the interior of a concave polygon so that the segment connecting them
                        is not wholly contained in its interior.
                    ¾   In a regular polygon, all sides are of the same length and all angles are of the same measure. A polygon
                        which is not regular is an irregular polygon.
                    ¾   The sum of interior angles of a polygon = (2n – 4) right angles
                                                                (2n – 4) × 90
                    ¾   Each interior angle of a regular polygon =          , where n is number of sides.
                                                                     n


                                                            MENTAL MATHS

                      1.  Choose the correct option.
                         (a)  In quadrilateral FISH, –FIS = –ISH = –SHF and –HFI = 150º, then find –FIS.
                             (i)  80º             (ii)  70º               (iii)  75º              (iv)  85º
                         (b)   Draw a line TALK and a parallelogram ALUM. If –KLU = 4 mº and –TAM = 5 mº, what are the
                             values of m and –AMU?
                             (i)  20 and 100º     (ii)  30 and 120º       (iii)  20 and 80º       (iv)  30 and 150º
                         (c)  A figure that is both a rectangle and a rhombus is:
                             (i)  kite            (ii)  rhombus           (iii)  square           (iv)  rectangle
                         (d)  A quadrilateral with two pairs of parallel sides is:
                             (i)  kite            (ii)  quadrilateral     (iii)  trapezium        (iv)  parallelogram
                         (e)  A figure in which the longer diagonal bisects the shorter one is:
                             (i)  kite            (ii)  parallelogram     (iii)  rhombus          (iv)  square
                         (f)  The angles of a quadrilateral are in the ratio 1 : 2 : 3 : 4. What type of a quadrilateral is formed?
                             (i)  Parallelogram   (ii)  Trapezium         (iii)  Rhombus          (iv)  Square


                176
   183   184   185   186   187   188   189   190   191   192   193