Slope of a straight line
Answers are for parents and teachers.
1
Find the slope of the line through (3, −2) and (7, 6), and its inclination angle to the nearest degree.
m = 8/4 = 2, θ ≈ 63°.
2
Show that (−1, −1), (1, 2) and (3, 5) are collinear.
Both slopes are 3/2.
3
Find the slope of a line perpendicular to the line through (0, 6) and (4, 0).
Slope −6/4 = −3/2, so the perpendicular has 2/3.
4
Prove that A(1, 1), B(5, 3), C(3, 7) is a right triangle and name the right angle.
AB has slope 1/2, BC has −2: right angle at B.
5
Find k so that the line through (1, 2) and (3, k) is parallel to the line through (0, 0) and (2, 6).
The second slope is 3; (k − 2)/2 = 3, so k = 8.