SOLUTION: Ina right triangle, sinB = 2/3, find the cosB

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Question 82091: Ina right triangle, sinB = 2/3, find the cosB
Answer by funmath(2933) About Me  (Show Source):
You can put this solution on YOUR website!
In a right triangle, sinB = 2/3, find the cosB
In right triangle trigonometry:
If we call the hypotenuse (the longest side of a right triangle): c
The side opposite of an angle: b
The side adjacent to the angle: a
Then sine=b/c
and cosine=a/c
AND
according to the pythagorean theorem: c%5E2=a%5E2%2Bb%5E2
Our b=2 and c=3, using the pythagorean theorem, we can find a:
%283%29%5E2=a%5E2%2B%282%29%5E2
9=a%5E2%2B4
9-4=a%5E2
5=a%5E2
sqrt%285%29=sqrt%28a%5E2%29
a=sqrt%285%29
Therefore: highlight%28cosB=sqrt%285%29%2F3%29
Happy Calculating!!!!