Please help with this asap thanks :) Question: What reason can be used to complete this proof?

m∠1=m∠3 because ∠1≅∠3.
m∠1+m∠2=m∠CXB and m∠2+m∠3=m∠AXD .
m∠1+m∠2=m∠AXD because you can substitute m∠1 for m∠3.
m∠CXB=m∠AXD by the transitive property of equality.
So, ∠AXD≅∠CXB.

Answers:
A: because that is given information

B: by the angle addition postulate

C: because you can measure them with a protractor

D: because m∠CXB=m∠AXD

Find the exact value of each of the following. in each case, show your work and explain the steps you take to find the value. (a) sin 17π/6 (b) tan 13π/4 (c) sec 11π/3

Girardo is using the model below to solve the equation . girardo uses the following steps: step 1 add 4 negative x-tiles to both sides step 2 add 1 negative unit tile to both sides step 3 the solution is which step could be adjusted so that gerardo's final step results in a positive x-value? in step 1, he should have added 4 positive x-tiles to both sides. in step 1, he should have added 3 negative x-tiles to both sides. in step 2, he should have added 4 negative unit tiles to both sides. in step 2, he should have added 1 positive unit tile to both sides.

Im literally having a mental breakdown