Trig – So far we have...

July 2011

Pythagoras c2 = a2 + b2

where c is the hypotenuse = the longest side

SOH-CAH-TOA

3D Problems

SOH-CAH-TOA

Pythagoras c2 = a2 + b2 so c = (a2 + b2 )^0.5 a2 = c2 - b2 so a = (c2 - b2 )^0.5 b2 = c2 - a2 so b = (c2 - a2 )^0.5

How to label a triangle

• H = Hypotenuse, which is always opposite the right angle and always the longest side. It does not move, Pythag: H2 = O2 + A2

• O = opposite which is the side opposite the angle we are interested in.

• A = Adjacent which lies between the right angle and the angle we are interested in.

Which formulae do I use?

Pythag or SOH-CAH-TOA

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Practical measurementUsing a Clinometer

3D Problem Solving

Today:Algebra recap

solve for xax2 + bx + c = 0

Working on problems in the text book and work book.

One group at a time measuring the classroom as per yesterday.

solve for xax2 + bx + c = 0

The

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Quad Formula from http://users.rcn.com/mwhitney.massed/quadratic_formula_proof.html

Ms Allan’s Wiki:

http://2011maths.wikispaces.com/NCEA+Level+1+Trig