Algebra 1
Linear Functions · Equations · Inequalities — 10 core problems
Algebra Progress0 / 10
⚡ Memory Keys — Linear Functions
Slope = RISE over RUN | y-intercept = where line CROSSES y-axis
slope = (y₂−y₁)/(x₂−x₁)
y = mx + b
rise/run
b = y-intercept
1
A line passes through the points (2, 5) and (6, 13).
What is the slope of this line?
m = (9 − 3) / (4 − 1) = 6 / 3 = 2 Slope = 2. Now try the problem above!
What is the slope of this line?
📖 Example First
Find the slope of a line through (1, 3) and (4, 9):m = (9 − 3) / (4 − 1) = 6 / 3 = 2 Slope = 2. Now try the problem above!
2
A line has the equation y = −3x + 7.
Which of the following is true?
Example: y = 4x − 2 → slope = 4, y-intercept = −2
Which of the following is true?
📖 Key Form
In y = mx + b: m is slope, b is y-intercept.Example: y = 4x − 2 → slope = 4, y-intercept = −2
3
A line passes through (0, 4) with slope −2.
What is the equation of this line?
What is the equation of this line?
Unit 2 · Linear Equations
⚡ Memory Keys — Linear Equations
ISOLATE the variable · do the SAME thing to BOTH sides · INVERSE operations undo each other
balance
inverse
isolate
distribute first
combine like terms
4
Solve for x:
3x − 8 = 16
3x − 8 = 16
5
Solve for x:
2(x + 5) = 18
Distribute: 3x − 6 = 12
Add 6: 3x = 18 → x = 6
2(x + 5) = 18
📖 Example
Solve 3(x − 2) = 12Distribute: 3x − 6 = 12
Add 6: 3x = 18 → x = 6
6
Solve for x:
5x − 3 = 2x + 9
5x − 3 = 2x + 9
Unit 3 · Inequalities
⚡ Memory Keys — Inequalities
FLIP the inequality sign when you multiply or divide by a NEGATIVE number!
flip when × or ÷ negative
> = open circle
≥ = closed circle
shade the solution
7
Solve the inequality:
−4x + 2 > 10 What is the correct solution?
−4x + 2 > 10 What is the correct solution?
8
Tom wants to spend at most $40 on books. Each book costs $6.
He already has $4 in his wallet. Which inequality shows
the maximum number of books n he can buy?
He already has $4 in his wallet. Which inequality shows
the maximum number of books n he can buy?
9
The solution to an inequality is x ≥ 3.
Which description correctly represents this on a number line?
Which description correctly represents this on a number line?
10
Solve for x:
(x/2) + 3 = 7 ⚠️ Watch out — many students divide before subtracting!
(x/2) + 3 = 7 ⚠️ Watch out — many students divide before subtracting!
Geometry
Triangles · Polygons · Circles — 10 core problems
Geometry Progress0 / 10
⚡ Memory Keys — Triangles
All angles add up to 180° · Exterior angle = sum of the two NON-adjacent interior angles
angle sum = 180
exterior = 2 remote interiors
Pythagorean: a²+b²=c²
c = hypotenuse
11
A triangle has angles of 52° and 73°.
What is the measure of the third angle?
What is the measure of the third angle?
12
A right triangle has legs of length 6 and 8.
What is the length of the hypotenuse?
What is the length of the hypotenuse?
📖 Formula
a² + b² = c²
The hypotenuse c is always the side OPPOSITE the right angle (the longest side).
13
In a triangle, two interior angles are 40° and 65°.
What is the measure of the exterior angle adjacent to the third interior angle?
(not the angle next to it!)
What is the measure of the exterior angle adjacent to the third interior angle?
📖 Exterior Angle Theorem
Exterior angle = sum of the TWO remote interior angles(not the angle next to it!)
Unit 5 · Polygons
⚡ Memory Keys — Polygons
Interior angle sum = (n − 2) × 180 | Each interior angle (regular) = sum ÷ n
(n−2)×180
n = number of sides
exterior angles always = 360°
regular = all equal
14
What is the sum of the interior angles of a hexagon (6 sides)?
15
Each interior angle of a regular octagon (8 sides) measures how many degrees?
16
A rectangle has length 12 cm and width 5 cm.
A diagonal divides it into two triangles.
What is the area of one triangle?
A diagonal divides it into two triangles.
What is the area of one triangle?
Unit 6 · Circles
⚡ Memory Keys — Circles
Circumference = 2πr = πd | Area = πr² | r = radius, d = diameter = 2r
C = 2πr
A = πr²
diameter = 2 × radius
π ≈ 3.14
17
A circle has a diameter of 10 cm.
What is its circumference? (Use π ≈ 3.14)
C = πd = 3.14 × 10 = 31.4 cm OR: C = 2πr = 2 × 3.14 × 5 = 31.4 cm
What is its circumference? (Use π ≈ 3.14)
📖 Example
Diameter = 10 → radius = 5C = πd = 3.14 × 10 = 31.4 cm OR: C = 2πr = 2 × 3.14 × 5 = 31.4 cm
18
A circle has a radius of 7 cm.
What is its area? (Use π ≈ 3.14)
⚠️ Tricky: many students use diameter instead of radius!
What is its area? (Use π ≈ 3.14)
⚠️ Tricky: many students use diameter instead of radius!
19
A circle has a circumference of 40π cm.
A central angle of 90° intercepts an arc.
What is the length of that arc?
Arc = (90/360) × 40π = (1/4) × 40π = 10π
A central angle of 90° intercepts an arc.
What is the length of that arc?
📖 Arc Length Formula
Arc = (central angle / 360) × circumferenceArc = (90/360) × 40π = (1/4) × 40π = 10π
20
An inscribed angle in a circle intercepts an arc of 120°.
What is the measure of the inscribed angle?
(The central angle EQUALS the arc; the inscribed angle is HALF)
What is the measure of the inscribed angle?
📖 Inscribed Angle Theorem
Inscribed angle = ½ × intercepted arc(The central angle EQUALS the arc; the inscribed angle is HALF)