Where did 12 come from I don't understand - Maths - Lines and Angles

Question

Where did 12 come from?? I don't understand

Bhavana Majji · Accepted Answer

Dear student
<img alt="" src=
"https://s3mn%20mnimgs%20com/img/shared/content_ck_images/ck_61040f4ac6a97%20jpg"
style="width: 1022px; height: 594px;">
Regards