Straight Line Flashcards
1
Q
distance formula
A
d=square root or (x2-x1)^2+(y2-y1)^2
2
Q
midpoint formula
A
(x1+x2 / 2, y1+y2 / 2)
3
Q
gradient formulas
A
- y2-y1/x2-x1
2. m=tantheta positive direction of x-axis
4
Q
types of gradient
A
- lines with positive gradients slope up from left to right
- lines with negative gradients slope down from right to left
- lines parallel to x-axis have a gradient of zero
- lines parallel to y-axis have an undefined gradient
5
Q
parallel lines
A
same gradient
6
Q
collinear
A
points which lie on the same straight line
- work out mab and mbc –> if same collinear
- must also share a common point
7
Q
perpendicular lines
A
at right angles with each other
m1xm2=-1
8
Q
equation of a straight line formula
A
y-b=m(x-a)
y=mx+c
9
Q
general form of equation of straight line
A
ax+by+c=0
10
Q
lines parallel to axis
A
- if line is parallel to x-axis y=c
- if line is parallel to y-axis x=k
11
Q
median
A
line through a vertex and the midpoint of the opposite side
12
Q
process of calculating median
A
- calculate midpoint of relevant line
- calculate gradient of line between midpoint and vertex
- find equation using gradient and either point
13
Q
altitude
A
line through a vertex, perpendicular to the opposite side
14
Q
process of calculating altitude
A
- calculate gradient of side perpendicular to altitude
- m1xm2=-1
- find equation using gradient and point
15
Q
perpendicular bisector
A
line which cuts through the midpoint of a line segment at right angles
