๐ Coordinate Plane (1st Quadrant)
Coordinate plane has x-axis (horizontal) and y-axis (vertical)
โถ Play Door 15Plotting Points Using (x, y) - Both Positive
What is a Coordinate Plane?
A coordinate plane is a flat surface with two perpendicular number lines:
โข x-axis (horizontal) โ left to right
โข y-axis (vertical) โ up and down
The first quadrant is where both x and y are positive numbers.
Ordered Pairs (x, y):
โข First number = x-coordinate (horizontal position)
โข Second number = y-coordinate (vertical position)
โข Always written as (x, y)
The Origin:
โข Point where axes meet
โข Coordinates: (0, 0)
Worked example
Problem: Plot point A(3, 5) on the coordinate plane.
- x = 3 โ move RIGHT 3 units from origin
- y = 5 โ move UP 5 units
- Mark point and label A
Answer: Mark point and label A
Reading Coordinates from a Map/Grid
Real-World Application
Maps use coordinate grids to show locations! Each location has a unique address (x, y).
How to Read a Grid Map:
โข Find the horizontal position (column) = x-coordinate
โข Find the vertical position (row) = y-coordinate
โข Read as (x, y)
Grid Map Example:
y=5 โ โ โ โ โ โ
y=4 โ โ ๐ โ โ๐ชโ โ
y=3 โ โ โ โ โ โ
y=2 โ๐ซโ โ โ โ๐ฅโ
y=1 โ โ โ โ โ โ
โโโโโดโโโโดโโโโดโโโโดโโโโ
x=1 x=2 x=3 x=4 x=5
House (๐ ) is at (2, 4)
School (๐ซ) is at (1, 2)
Store (๐ช) is at (4, 4)
Hospital (๐ฅ) is at (5, 2)
Worked example
Problem: On a zoo map, the lions are at (3, 7) and elephants at (8, 4). Which animal is more to the right?
- x-coordinate tells right/left position
- Lions: x=3, Elephants: x=8
- 8 > 3, so elephants are more to the right
- Answer: Elephants
Answer: Answer: Elephants
Horizontal & Vertical Distance Between Points
Finding Distance on a Coordinate Plane
Since we're only in the first quadrant, all coordinates are positive. Distances are always positive.
Horizontal Distance (Left to Right):
โข Points have the same y-coordinate
โข Distance = |xโ - xโ|
Vertical Distance (Up and Down):
โข Points have the same x-coordinate
โข Distance = |yโ - yโ|
Distance Formula for Same Row/Column:
Horizontal: |xโ - xโ|
Vertical: |yโ - yโ|Note: | | means "absolute value" (always positive)
Worked example
Problem: Find the distance between A(3, 5) and B(8, 5).
- Same y-coordinate (y=5) โ horizontal distance
- Distance = |8 - 3| = 5
- Answer: 5 units
Answer: Answer: 5 units