Essential Algebra and Geometry Formulas Reference Sheet

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πŸ“„ Maths Cheat Sheet – Page 1 (Equations & Linear Relationships)

🟦 Equations

  • 1-step:

    X+to=b⇒x=b-to,tox=b⇒x=b/tox + a = b \Rightarrow x = ba, \quad ax = b \Rightarrow x = b/ax+to=b⇒x=b-to ,to x=b⇒x=b / a
  • 2-step:

    Tox+b=c⇒x=(c-b)/toax + b = c \Rightarrow x = (cb)/ato x+b=c⇒x=( c-b ) / a
  • Brackets:

    • Expand:to(b+c)=tob+toca(b+c) = ab + aca ( b+c )=ab+a c

    • Factorise:tob+toc=to(b+c)ab + ac = a(b+c)ab+a c=a ( b+c )

  • Fractions: Clear denominators first

  • Check: Substitute back

Worked Example (Rectangle):

  • l=w+3, P=14l = w+3, \, P=14l=w+3 ,P=14

2((w+3)+w)=14β‡’4w+6=14β‡’w=2β‡’l=52((w+3)+w)=14 \Rightarrow 4w+6=14 \Rightarrow w=2 \Rightarrow l=52 (( w+3 )+w )=14β‡’4 w+6=14β‡’w=2β‡’l=5

🟩 Linear Relationships

  • Equation of a line: and=mx+cy=mx+cand=m x+c

    • m=m =m= gradient (slope = rise Γ· run)

    • c=c =c= y-intercept (where line crosses y-axis)

  • Gradient formula:

M=and2-and1x2-x1m = \frac{y_2 - y_1}{x_2 - x_1}m=x2-x1and2-and1​
  • Slope meaning:

    • Positive β†’ line rises ↑

    • Negative β†’ line falls ↓

    • Zero β†’ horizontal β€”

    • Undefined β†’ vertical |

  • How to find slope: rise/run between 2 points

  • How to find y-intercept: putx=0x=0x=0 OR substitute a point intoand=mx+cy=mx+cand=m x+c

  • Distance formula: (x2-x1)2+(and2-and1)2\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}( x2-x1)2+( and2-and1)2​

  • Midpoint formula: (x1+x22,and1+and22)\left(\frac{x_1+x_2}{2}, \frac{y_1+y_2}{2}\right)(2x1+ x2​,2and1+ and2​)

  • Parallel lines: same slope

  • Perpendicular lines: slopes Γ— = βˆ’1


🟩 Cartesian Plane Tips

  • Axes: x horizontal, y vertical, origin (0,0)

  • Quadrants: I(+,+), II(βˆ’,+), III(βˆ’,βˆ’), IV(+,-)

  • Plot line: start at y-int (0,c), use slope, draw line

  • Tips: label points, use ruler, check coordinates


πŸ“„ Maths Cheat Sheet – Page 2 (Geometric Figures & Angles)

πŸŸ₯ Geometric Figures

Congruence & Similarity

  • Congruent = same shape & size

  • Triangle congruence: SSS, SAS, AAS, RHS

  • Triangle similarity: AAA

Triangles:

  • Angles sum = 180Β°

  • Exterior angle = sum of opposite interior angles

  • Types:

    • Isosceles β†’ 2 sides & angles equal

    • Equilateral β†’ all sides & angles 60Β°

    • Right β†’ Pythagoras:to2+b2=c2a^2+b^2=c^2to2+b2=c2

Quadrilaterals (angles sum = 360Β°):

  • Parallelogram β†’ opp sides // & =, opp angles =

  • Rectangle β†’ 4 right angles, opp sides =

  • Rhombus β†’ all sides =, diagonals βŸ‚

  • Square β†’ rectangle + rhombus

  • Trapezium β†’ 1 pair of parallel sides

Circles:

  • Angle in semicircle = 90Β°

  • Angle at center = 2 Γ— angle at circumference

  • Tangent βŸ‚ radius

Transformations:

  • Rotation = turn around a point

  • Translation = slide

  • Reflection = flip over a line


πŸ”Ί Z, F, T Angles

  • Z-angle (alternate angles) β†’ equal, opposite sides of transversal

  • F-angle (corresponding angles) β†’ equal, same relative position

  • T-angle (co-interior) β†’ sum = 180Β°

How to solve:

  1. Z β†’ set alternate angles equal β†’ solve

  2. F β†’ set corresponding angles equal β†’ solve

  3. T β†’ sum of co-interior angles = 180Β° β†’ solve



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