In a right triangle abc, cd is an altitude, such that ad=bc. find ac, if ab=3 cm, and cd= square root 2 cm.

      ΔACB                                               ΔCDA

AC² + BC² = AB²                           AD² + CD² = AC²  

          BC² = AB² - AC²                 BC² + CD² = AC²        (AD=BC is given)

                                                                 BC² = AC² - CD²

                         AB² - AC² = AC² - CD²         (both sides were = to BC²)

                         AB² + CD² = 2AC²

                         (3)² + (√2)² = 2AC²            (AB=3 and CD=√2 were given)

                          9  +   2    = 2AC²

                               11        = 2AC²

                                       = AC²

                                    = AC

                                     = AC

i think it is everything has to equal 180 so, if i correct 4=c. 6=d. 8=a. 7=b. and the last question would be c. because they are parallel lines and they are congruent.

step-by-step explanation:

the reason everything has to equal to 180 is because that is how it works. i'm guessing that is its rule. 4 and 8 are congruent and parallel so, that would be 30+30 because they have the same number. it would equal 60. 6 and 7 are congruent and parallel so, that would be 30+30 because they have the same number. it would equal 60. 60+60 is 180. so, now you have your answer

its kind of blurry. can you put a clearer pic?

step-by-step explanation: