Опорні конспекти з теми звичайні дроби. Математика 5 клас

 

                              ІІ. Правильні і неправильні дроби

 

 

 

 

   1)

 

 

 

 

 

 

 

   2)

 

 

 

 

 

 

 

   3)                                                                    =

 

 

 

 

 

 

 

 

 

   4)                                              =

 

 

 

 

 

 

 

 

 

 

      5)                                               =                                  +

 

 

 

     6) _9  4                       знаменник дробової частини           9          1                             

           8  2                       ціла частина                                      –– = 2 ––                                 

           1                           чисельник дробової частини           4          4

 

 

 

IV. додавання і віднімання дробів з однаковими знаменниками

 

 

 

 1)                                          +                                       =

 

 

 

                       _1_                  +                 _2_                =                 _3_

                         4                                         4                                       4

 

 

 2)                                                               треба                          і

 

 

 

 

 

 

 3)

 

 

 

 

 

 4)                                       –                                       =

 

 

 

                       3_                 –                 1_                  =                   2_

                       4                                      4                                         4

 

  5)

                                                                   треба                         і

 

 

 

 

 

 

   6)            

 

 

Площі трикутників

Довільний трикутник

        1                                                                                         _________________

S = –– ah;                                           Формула Герона  S = √p(p – a)(p – b)(p – c) ,

        2                                                                                      a + b + c                                

       1                                                                            де p = –––––––               

S = –– ab sin γ;          b           h_a           c                                          2

       2                                                                                          a b c

         γ                                                       S = –––––

                                                                                                   4R

                                            а

де  R – радіус описаного кола       S = r p ,      де  r – радіус вписаного кола

 

 

Правильний трикутник 

 

 

                                                       _

                                                 a²√3

                                           S = –––                                                               

                                                   4                         a                         a

 

                                                                                           a

 

 

Прямокутний трикутник

 

                                                                                                              B

                             1

                 S = –– ab;   

                             2

 

                           1                                                              c                   a

                   S = –– ch_c;

                           2                                                                        h_c

                           1

                   S = –– bc sin A;

                           2                                                  A            b                C

                           1

                   S = –– ac sin B

                           2