Answer: 95°
Step-by-step explanation: We are given information for Angles 1 and 4, which happen to be vertical angles, meaning they are congruent. Because of this, we can say 3x+10=4x-15, therefore x=25. Angles 1,2,3 and 4 must add up to 360°, and since we know angles 1 and 4 are 85° (3*25 + 10 = 85), we can find angles 2 and 3. 360° - 85° - 85° = Angle 2 + Angle 3. Angle 2 + Angle 3 = 190, and because Angles 2 and 3 are vertical angles and therefore congruent, we can divide 190 by 2 and get that Angles 2 and 3 equal 95°. Because lines b and c are parallel, any corresponding angles created by a transversal are congruent. This basically means Angles 3 and 7 must be congruent, therefore Angle 7 = 95°
Congruent - same meaning as equal
Vertical Angles - each of the pairs of opposite angles made by two intersecting lines.