Essential Algebra and Geometry Formulas Reference Sheet
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π Maths Cheat Sheet β Page 1 (Equations & Linear Relationships)
π¦ Equations
1-step:
X+to=bβx=b-to,tox=bβx=b/tox + a = b \Rightarrow x = ba, \quad ax = b \Rightarrow x = b/ax+to=bβx=b-to ,to x=bβx=b / a2-step:
Tox+b=cβx=(c-b)/toax + b = c \Rightarrow x = (cb)/ato x+b=cβx=( c-b ) / aBrackets:
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,βP=14l = w+3, \, P=14l=w+3 ,P=14
π© 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:
Slope meaning:
Positive β line rises β
Negative β line falls β
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)2β
Midpoint formula: (x1+x22,and1+and22)\left(\frac{x_1+x_2}{2}, \frac{y_1+y_2}{2}\right)(2x1+ x2β,2and1+ and2β)
Parallel lines: same slope
Perpendicular lines: slopes Γ = β1
π© Cartesian Plane Tips
Axes: x horizontal, y vertical, origin (0,0)
Quadrants: I(+,+), II(β,+), III(β,β), IV(+,-)
Plot line: start at y-int (0,c), use slope, draw line
Tips: label points, use ruler, check coordinates
π Maths Cheat Sheet β Page 2 (Geometric Figures & Angles)
π₯ 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 β
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 β radius
Transformations:
Rotation = turn around a point
Translation = slide
Reflection = flip over a line
πΊ 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:
Z β set alternate angles equal β solve
F β set corresponding angles equal β solve
T β sum of co-interior angles = 180Β° β solve