Mathematics
Grade 8
15 min
Find a missing coordinate using slope
Find a missing coordinate using slope
Tutorial Preview
1
Introduction & Learning Objectives
Learning Objectives
Define slope and its components (rise and run).
Correctly apply the slope formula given two points.
Set up an algebraic equation using the slope formula when one coordinate is unknown.
Solve for a missing x-coordinate using the given slope and two points.
Solve for a missing y-coordinate using the given slope and two points.
Verify their calculated missing coordinate by re-calculating the slope.
Identify and correct common errors when finding missing coordinates using slope.
Ever wondered how engineers ensure a ramp has the perfect incline, or how a ski slope maintains its steepness? ⛷️ It's all about understanding slope!
In this lesson, you'll learn how to use the concept of slope to find a missing coordinate of a point on a line. This skill...
2
Key Concepts & Vocabulary
TermDefinitionExample
Slope (m)Slope is a measure of the steepness and direction of a line. It describes how much the line rises or falls vertically for every unit it moves horizontally.A road with a slope of 1/10 rises 1 unit for every 10 units it moves horizontally.
CoordinatesCoordinates are a set of values that show an exact position on a graph. They are written as an ordered pair (x, y), where 'x' is the horizontal position and 'y' is the vertical position.The point (3, 5) means 3 units to the right of the origin and 5 units up.
Ordered PairAn ordered pair is a pair of numbers (x, y) that represents a single point on a coordinate plane. The order matters: (2, 3) is different from (3, 2).The starting point of a line might be (x1, y1) and the ending point (x2, y2)....
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Core Formulas
The Slope Formula
$m = \frac{y_2 - y_1}{x_2 - x_1}$
This formula calculates the slope ($m$) of a line given two distinct points $(x_1, y_1)$ and $(x_2, y_2)$. The numerator represents the 'rise' (change in y) and the denominator represents the 'run' (change in x). Remember that the order of subtraction must be consistent for both x and y coordinates.
Using the Slope Formula to Find a Missing Coordinate
Substitute known values into $m = \frac{y_2 - y_1}{x_2 - x_1}$ and solve for the unknown variable.
When you know the slope ($m$) and three out of the four coordinates of two points (e.g., $(x_1, y_1)$ and $(x_2, ?)$), you can plug these values into the slope formula. This will create an algebraic equation that you can then solve to find the missing coordina...
4 more steps in this tutorial
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Sign Up Free to ContinueSample Practice Questions
Easy
A line passes through (2, 8) and (x, 4). If the slope is -2, what is the value of x?
A.-2
B.0
C.4
D.6
Easy
The points (5, y) and (1, 3) are on a line with a slope of 1. What is the value of y?
A.-1
B.4
C.7
D.8
Easy
Which formula is used to calculate the slope (m) of a line passing through two points, $(x_1, y_1)$ and $(x_2, y_2)$?
A.m = (x₂ - x₁)/(y₂ - y₁)
B.m = (y₂ - y₁)/(x₂ - x₁)
C.m = (y₂ + y₁)/(x₂ + x₁)
D.m = (y₂ - x₂)/(y₁ - x₁)
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