14. Angles 4 and 6 are supplementary, because they are on the same line. Supplementary angles add up to 180 degrees, and a line must be 180 degrees.
15. Angles 1 and 8 are congruent, because they are alternate exterior angles
16. m = y2 - y1 / x2 - x1 m = 7 - 2 / 4 - 5 m = 5 / -1 m = -5
17. m = 3 - 3 / 7 - (-5) m = 0 / 12 m = 0
18. m = 1 - (-2) / 5 - (-4) m = 3 / 9 m = 1/3
19. A = (0, 3) - B = (3,0) m = 0 - 3 / 3 - 0 m = -3 / 3 <em>m = -1</em> C = (0, -2) - D = (4, 2) m = 2 - (-2) / 4 - 0 m = 4 / 4 <em>m = 1</em> Perpendicular, because the slopes are opposite reciprocals. 20. E = (1, 2) - F = (0, 0) m = 0 - 2 / 0 - 1 m = -2 / -1 <em>m = 2</em> G = (1, -3) - H = (3, 0) m = 0 - (-3) / 3 - 1 <em>m = 3 / 2</em> Neither, because the slopes are different.
21. I = (0, 1) - J = (2, -4) m = -4 - 1 / 2 - 0 <em>m = -5/2</em> K = (-1, -2) - L = (4, 0) m = 0 - (-2) / 4 - (-1) <em>m = 2/5</em> Perpendicular, because the slopes are opposite reciprocals.
22. M = (-2, 2) - N = (2, 2) Horizontal line <em>m = 0</em> O = (3, 0) - P = (-3, 0) Horizontal line <em>m = 0 </em>Parallel, because the slopes are the same. <em> </em>23. Angle 2 is congruent to angle 1 because of the alternate exterior angle theorem. Angle 1 is congruent to angle 3 because of the vertical angle theorem. Angle 2 is congruent to angle 3 because of substitution. Line l is parallel to line m because the corresponding angles are congruent.
23. Given: Transversal r cuts lines l and m: <2 = <1 Prove: l || m
<u> Statements | Reasons</u><u> </u> 1. <2 ≡ <1 | 1. They are congruent. 2. <1 ≡ <3 | 2. They are congruent. 3. <2 ≡ <3 | 3. They are parallel. 4. l || m | 4. They are parallel.
All triangles have three sides with specific lengths and angles, but a scalene triangle is a kind of triangle that has each of its three sides to be of different lengths and angles.
Hence, a triangle that measures 39°, 104°, and 37° definitely has three sides with different lengths and angles.