Pythagoras and
trigonometry
trigonometry
(right angled triangles)
Use these rules to work out sine, cosine and tangent in trigonometry
Random trigonometry
From subtangent
From subtangent
b
a
h
In this triangle h is the hypotenuse
a and b are the other two sides
a and b are the other two sides
b
a
h
A
B
In this triangle h is the hypotenuse
a is the side opposite angle A and b is
the side opposite angle B
a is the side opposite angle A and b is
the side opposite angle B
Sin A = a/h if a = 3 and h=6
Sin A = 3/6 =0.5
Angle A = 30
Sin A = 3/6 =0.5
Angle A = 30
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You can rearrange all the equations
eg sin B = b/h
b = sin B x h
And
h = b/sin B
cos A = b/h
and tan A = a/b
You can rearrange these in same way as you did
with sine
eg sin B = b/h
b = sin B x h
And
h = b/sin B
cos A = b/h
and tan A = a/b
You can rearrange these in same way as you did
with sine
With trigonometry you can find angles in right angled
triangles if you know two sides and sides if you
know an angle and a side. All you have to do
Is choose the correct equation
You can also use combinations of pythagoras
And trigonometry
triangles if you know two sides and sides if you
know an angle and a side. All you have to do
Is choose the correct equation
You can also use combinations of pythagoras
And trigonometry
