Question

I don't know how they got the answer
http://awesomescreenshot.com/0b33h9pwd0
Please explain step by step
(studying for upcoming SAT)

Answer 1

if r = 91, then what is s?

Answer 2

91?

Answer 3

nope..
do u know r+s = 180

u know the reason?

Answer 4

For reference, some || line rules:
http://www.regentsprep.org/Regents/math/geometry/GP8/Lparallel.htm

Answer 5

I thought so but I wasn't sure so I left that alone and thank you @e.mccormick I'll look into that.

s=89

Answer 6

Then t+u = 89 + 89 = 178 ? @midhun.madhu1987

Answer 7

yeah... thats cooool

Answer 8

thank you both

Answer 9

yw :)