Answer:
m<6=80
Explanation:
In angles, a straight line equals 180 degrees. So m<8 + m<9 = 180, meaning if m<8=80, m<9= 100 . M<9 and m<6, also make a straight line and we know that m<9=100. So m<6 must equal 80.
There is also a rule, saying that angles diagonal to each other equal the same so m<6= 80 also.
Hope this helps.