Geometry, please help

I believe that number 7 is true.

Step-by-step explanation:

8. Is not a vertical angle because 3 and 3 do not look the same. The line is clearly gone on one side.

9. Is also wrong because both angles do not make a 90 degree angle.

10. Is wrong because both angles make a 90 degree angle when it should make a be 180 degrees.

( I'm learning this subject right now so it might be wrong. Tell me if I go this right.)

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