Pythgoras and Trig Flashcards
What is the rule we use when using pythagoras to find an unknown side?
a2 + b2 = c2
How do you use pythagoras to find an unknown side that is not the hypotenuse?
Substitute the values into the formula a2 + b2 = c2 in which the hypotenuse is the always substituted into c2
Why do we use trigonometry?
To find an angle or side of interest
What are the three sides a right angle triangle called?
Hypotenuse, Adjacent, Opposite
Pythagoras and Trigonometry only work on what sort of triangles?
Right angled
What does SOH stand for?
Function Sine, Opposite and Hypotenuse sides
What does CAH stand for?
Function Cosine, Adjacent and Hypotenuse sides
What does TOA stand for?
Function Tangent, Opposite and Adjacent sides
The first step when trying to find an unknown side using an angle is…
… figure out which sides you have eg Opposite and Hypotenuse.
The second step when trying to find an unknown side using an angle is…
… think what ratio do I need. Sine, Cosine or Tangent. SOH CAH TOA
What is the calculation for finding an unknown side when the angle and the Hypotenuse are known and the Adjacent side is the unknown?
Adj = Sine angle x Hypotenuse
unknown side = Ratio angle x known side
What is the calculation for finding an unknown angle?
Ratio-1 = (known side/known side)*
*Use a formula to figure this out O we do not know the
S H
angle so we are left with only the O and H. The O is above the H so the equation is X = Sin-1( O/H)
Do we use the ratio on its own or Ratio-1 when finding an unknown side?
Ratio on its own
Do we use the ratio on its own or Ratio-1 when finding an unknown angle?
Ratio-1
How do you use a formula triangle?
Figure out which sides you have. Depending on which sides you have you will put either SAH, CAH, or TOA in your formula triangle. Cross out the unknown value and you will be left with the formula.
