pythagoras and trigonometry notes

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pythagoras' theorem

a squared + b squared = c squared   (C grade)

  • only works for right angled triangles
  • uses 2 sides to find the 3rd side
  • make sure you get the numbers in the right place
  • c is the longest side (called the hypotenuse) and it's always opposite the right angle
  • check that your answer is sensible

use pythagoras to find the distance between two points (c grade)

  • draw a sketch to show the right-angled triangle
  • find the lengths of the shorter sides of the triangle
  • use pythagoras to find the length of the hypotenuse

trigonometry- Sin, Cos, Tan

the 3 trigonometry formulas (b grade)

  • three basic trig formulas
  • each one links two sides and an angle of a right-angled triangle
  • sin x = opposite divided by hypotenuse
  • cos x = adjacent divided by hypotenuse
  • tan x = oppositve divided by adjacent
  • hypotenuse is the longest side
  • opposite is the side opposite the angle being used
  • adjacent is the side next to the angle being used
  • work out which two sides of the triangle are involved in the question
  • pick the formula that involves those sides
  • to find the angle- use the inverse followed by sin, cos or tan
  • make sure your calculator is in deg mode
  • your calculator will display sin, cos or tan to the power of -1
  • only works for right angled triangles

angles of elevation and depression (b grade)

  • angle of depression is angle downwards from the horizontal
  • angle of elevation is angle upwards from the horizontal



Incredibly helpful, thank you so so much


wonderful these notes were helpful

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