Reasoning may vary. One way to find the measures of the angles is as follows: m5 is 45°, since it is a vertical angle to the given 45° angle. Since angles inside a triangle add up to 180°, m7 must be 70°. This means that m6 is 110° because m6 and m7 add up to 180°. Similarly, m8 must be 115°. m11 is 110°, since it is vertical to 6. m12 is 70°, m10 is 115°, and m9 is 65°. Since 12 and 3 are corresponding, m3 is 70°. Similarly, since 9 and 4 are corresponding, m4 must be 65°. Finally, using vertical angles, m1 is 65°, and m2 is 70°.
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