Alberta Free Tutoring And Homework Help For Math 20-1

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The point (-9, 40) is on the terminal arm of an angle,  $\theta$θ in standard position. 

a. what is the length of the line segment connecting the orgin to the point (-9,40)

b. Determine the measure of  $\theta$θ , to the nearest tenth of a degree. 

7 years ago

Answered By Emily H

The first part of this problem can be solved by aimple application of the Pythagorean theorem:

 $x=\sqrt{9^2+40^2}$x=92+402 

 $x=41$x=41 

For the second part, you take the inverse tangent of the ratio of the sides:

 $\tan\alpha=\frac{40}{9}$tanα=409  

 $\alpha=\tan^{-1}\left(\frac{40}{9}\right)$α=tan1(409 ) 

 $\alpha=77.3^{\circ}$α=77.3? 

To account for the angle lying in the third quadrant, add 180 degrees.

 $\theta=180^{\circ}+\alpha$θ=180?+α 

 $\theta=257.3^{\circ}$θ=257.3? 

 

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