Problem 10
These are vertical angles because they are opposite one another when the X shape forms at the center. Vertical angles are congruent, so both are 70 degrees. Both angles are acute angles.
Answer: vertical, acute
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Problem 11
These are adjacent angles. They share a common segment between them. That segment being DX. Note how the letters D and X are part of DXC and AXD. Also, the D and X are next to each other in the sequences DXC and AXD.
Angle DXC is 70 degrees (see problem 10), so it is acute. Angle AXD is 105 degrees, so it is obtuse, as it is larger than 90.
Answer: Adjacent, DXC is acute, AXD is obtuse
note: you could say collectively that angles DXC and AXD combine to a straight angle as they add to 180 degrees (aka a straight line)
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Problem 12
Like with problem 10, these angles are vertical. This is the top and bottom pair of angles. Both are 105 degrees and are obtuse
Answer: vertical, obtuse
