Page 149 - BS 8 Matematika 2
P. 149

No.                Prisma                    Luas permukaan prisma

                                                           Luas  = 2 × I + II + III + IV + V
                                  8 cm                           = 2 × (8 × 6) + (6 × 40)
                           6 cm     I   6 cm                       + (8 × 40) + (6 × 40) +
                                                                   (8 × 40)
                           6 cm 8 cm    6 cm 8 cm
                                                                 = 2 × (8 × 6) + (6 + 8 + 6
                                                                   + 8) × 40
                          40 cm  II  III  IV    V      40 cm       × 40
                  2.                                             = 2 × (8 × 6) + 2 × (8 + 6)

                                                                 = 2 × (48) + 2 × (14) × 40
                           6 cm 8 cm    6 cm 8 cm                = 96 + 28 × 40

                           6 cm     I    6 cm                    = 96 + 1.120
                                                                 = 1.216
                                  8 cm
                                                           Jadi, luasnya adalah 1.216 cm 2.


                                                           Luas  = 2 × I + II + III + IV + V
                                                                   + VI + VII
                                  10 cm
                           10 cm         10 cm                   = 2 × I + II + II + II + II
                                     I                             + II + II
                                         10 cm
                                                                 = 2 × I + 6 × II
                         10 cm    10 cm           10 cm
                                                                            1
                                                                 = 2 × (6 ×   × 10 × 5 3)
                                                                            2
                           II  III IV    V   VI VII    30 cm
                                                                   + 6 × (10 × 30)
                       30 cm
                                                                 = 2 × (150 3) + 6 × (300)
                         10 cm    10 cm          10 cm
                  3.
                                         10 cm                   = 300 3 + 1.800
                                     I                     Jadi, luasnya adalah (300 3 +
                           10 cm         10 cm
                                  10 cm                            1.800) cm 2.

                                                           Keterangan:
                         10 cm10 cm           10 cm  10 cm   t  =  10 −  5 2
                                                                    2
                                                 t
                                                                      −
                                                              =   100 25
                                               10 cm
                            10 cm                             = 75
                       10 cm
                                                                = 5 3





                  140     Kelas VIII SMP/MTs                                  Semester II
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