ACT Math 4.1 Coordinate Geometry

ACT Math: Coordinate Geometry Drill 4, Problem 1. Find the equation of the line described.

ACT Math	Coordinate Geometry
ACT Mathematics	Coordinate Geometry
Algebra	Coordinates and Graphs
Coordinate Geometry	Parallel and perpendicular lines
Foreign Language	Arabic Subtitled Chinese Subtitled Korean Subtitled Spanish Subtitled
Geometry	Coordinate Geometry
Language	English Language
Product Type	ACT Math

00:20

the land of Y equals MX plus B

00:23

were M is the slope of a line. The slope of a line

00:26

perpendicular to that line is the negative

00:29

inverse of that form. In this example the slope is negative 1/2

00:35

so we just need that negative reciprocal so that'll be positive

00:39

2 over one or just positive 2. So we can get rid of B and C as potential answers.

00:44

We also know that one point this perpendicular line contains is

00:49

8 , 2. So all we need to do is plug in these points

00:54

into Y equals MX plus B so

00:57

we get 2 equals 2 times

01:00

8 plus B and we have 2 equals 16 plus B

01:04

or B equals -14 and we have Y equals 2x -14

01:09

there you go. The answer is E.