TRIANGLES!

TRIANGLES!

1. When to use Pythagoras....

   • a^2 + b^2 = c^2
   • 5^2 + 24^2= c^2 You then square root the answer to equal 24.5 (1d.p)

2. SOH CAH TOA

   • This only works with right angled triangles. If you want to find an angle with 2 sides you have to use SOH CAH TOA. Label the sides, hyp, opp and adj and look for the function
   • To find an angle
   • If you want to find a side and you already have a side and an angle you use SOH CAH TOA. If you have 2 sides, you can just use Pythagoras. If x is at the top, you times and if x is at the bottom, you divide.

3. SINE RULE

   • You can use the sine rule when you do not have a right angled triangle and can find diagonal opposites. By substituting the values in the formula you can find a side (you need at least one side and two angles).
   • You can also use the sine rule to find an angle. You need two sides and an angle (diagonally opposite). The formula is rearranged.

4. COSINE RULE

   • W also use this rule when the triangle is not right angled. To find an unknown side we need two sides and an angle in the form of an "ANGLE SANDWICH"
   • To find an angle, you have to rearrange the formula and substitute the values. You have three sides.
   • REMEMBER THAT A IS ALWAYS OPPOSITE THE ANGLE

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