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Help????? I don’t know which is right

Help????? I don’t know which is right-example-1
User Apocalisp
by
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1 Answer

4 votes

Answer:

C

Explanation:

Given

tanθ =
(1)/(2) =
(opposite)/(adjacent)

This is a right triangle with legs 1 and 2

Using Pythagoras' identity

hypotenuse² = 1² + 2² = 1 + 4 = 5 ( take square root of both sides )

hypotenuse =
√(5)

θ is in the 3rd quadrant where sinθ < 0 , then

sinθ =
(opposite)/(hypotenuse) = -
(1)/(√(5) ) ← rationalise the denominator

= -
(1)/(√(5) ) ×
(√(5) )/(√(5) )

= -
(√(5) )/(5) → C

User Rgullhaug
by
7.4k points