are you asking for the 9th term or the 10th term?
I believe it’s D not 100% sure but yea
see the attached figure to better understand the problem
we know that
1) If angle 1 and angle 2 are complementary angles
then
m∠1+m∠2=
------> equation A
2) If angle 1 and angle 2 are congruent angles
then
m∠1=m∠2 ------> equation B
Substitute equation B in equation A
m∠1+(m∠1)=
2m∠1=
m∠1=
therefore
<u>the answer is</u>