Real numbers,grade 9, question 21

01/03/2017 Grade 9 3,528

A,B,C,D are the vertices of a quadrilateral

  1. Choose the correct answer:
  • AB = 

    \frac{{\sqrt{{7^2}-{2^2}\times10}}}{{\left({\sqrt 5-2}\right)\left({\sqrt 5+2}\right)}}

    then AB =

a) 

\sqrt3

                        b) 3                                c)

6\sqrt{15}

  • BC = x2-7x+9 where x = 1, then BC =

a)  15                                b) 17                                c) 3

  • CD = 

    \frac{{0.2\times{{10}^3}+0.4\times{{10}^2}}}{{{{(0.2)}^3}\times{{10}^4}}}

    then CD =

a) 24                                 b) 3                                 c) 30

  • AD = 

    \frac{{\frac{{m+7}}{4}}}{{\frac{{-1}}{m}}}

    where m = -3, then AD =

a) -7.5                              b) 7.5                              c) 3

2) what must be the length of AC so that ABCD is a square?