Maths Equations

• Simple interest: I=PTR/100
• To find the amount in simple interest: A=P+I
• Compound Interest: A=P(1+-R/100)^T
• Speed: Average S=Total distance/Total time
• Gradient: y2-y1/x2-x1
• In distance-time graphs with the gradient you find speed/velocity
• In velocity-time graphs with the gadient you find acceleration/deceleration
• Area under the graph = distance travelled
• Area of rectangle: LxB
• Area of triangle: bxh/2
• Area of trapezium: 1/2(a+b)h
• Error%: Actual error/True value x 100%
• To express quantity A as a percentage of quantity B: A/B x 100%
• General equation of a line: y=mx+c
• Parallel lines have the same gradient
• Acute angle: less than 90°
• Obtuse angle: between 90° and 180°
• Reflex angle: between 180° and 360°
• Angles at a straight line add up to 180°
• Angles at a point add up to 360°
• The sum of all 3 angles in any triangle add up to 180°
• The sum of all 4 angles in any quadrilateral add up to 360°
• Vertically opposite angles are equal

  
• Parallel lines: corresponding angles are equal(F)

  
• Parallel lines: alternate angles are equal(Z)

  
• Parallel lines: interior angles add up to 180°(U)

  
• Complementary angles: when the sum of 2 angles is 90°
• Supplementary angles: when the sum of 2 angles is 180°
• Circle Theorems: Angles in the same segment are equal
• Circle Theorems: Angle at the centre is twice the angle at the circumference
• Circle Theorems: Angle in a semi-circle is 90°
• Circle Theorems: Opposite angles of a Cyclic Quadrilateral are supplementary (add up to 180°)
• Circle Theorems: The exterior angle of a cyclic quadrilateral is equal to its opposite interior angle
• Circle Theorems: Angle between tangent and radius is perpendicular (90°)
• Circle Theorems: Two tangents to a circle from a common point are equal in length
• Equilateral Triangle: All sides + angles are equal
• Isosceles Triangle: 2 sides + 2 angles are equal
• Scalene Triangle: No sides + angles are equal
• Similar Triangles (3 conditions): AAA, RRR, RAR

  A (angle), R (ratio)
• Congruent Triangles (4 conditions): SSS, SAS, AAS, RHS

  A (angle), S (side), R (right angle), H (hypotenuse)