HELP HELP PLS HELP I WILL BRAINLIST U

Which of the following vectors are orthogonal to (2,1)? check all that apply

If a distance of 75 yds is measured back from the edge of the canyon and two angles are measured , find the distance across the canyon angle acb = 50° angle abc=100° a=75 yds what does c equal?

Given: ab ≅ bc and ao ≅ oc ok − angle bisector of ∠boc find: m∠aok