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Gerald is 6 feet tall and his daughter Imelda is 4 feet tall. If they stand 9 feet apart, at about what angle does Imelda have to look up to see the top of her father's head?

 Jan 30, 2016

Best Answer 

 #1
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+15

If you draw the picture of this you will see that her eyes are 4 feet off of the ground at one vertex of a triangle and another vertex is at 4 feet off of the ground on her father and the other vertex is at her father's head....

 

Two legs of the triangle are 2 and 9 feet    of a RIGHT triangle    the TANGENT of the angle is   2/9  so the angle is

arctan(2/9) = 12.53 degrees

 Jan 30, 2016
 #1
avatar
+15
Best Answer

If you draw the picture of this you will see that her eyes are 4 feet off of the ground at one vertex of a triangle and another vertex is at 4 feet off of the ground on her father and the other vertex is at her father's head....

 

Two legs of the triangle are 2 and 9 feet    of a RIGHT triangle    the TANGENT of the angle is   2/9  so the angle is

arctan(2/9) = 12.53 degrees

Guest Jan 30, 2016
 #2
avatar+2592 
+10

Since the height difference is 2, theams that 2 is one fo the side lengths

You can find this using the fact that the triangle's base is starts at roughly the top of Imelda's head.

The other side length is 9, since they are 9 feet apart.

We use the pythagorem theorem to find the hypotenuse a^2+b^2=c^2

4+81=sqrt(85)

Using sin(x)=2 over sqrt(85) we can find the angle of elevation

asin(2/sqrt(85)) = 0.218668945874

This is in radians

We can multiply by 180/pi to turn this into degrees

0.218668945874*((180)/pi) = 12.5288077091548361

We round to the nearest degree and our anwser is 13 degrees of elevation

 Jan 30, 2016
 #3
avatar+2592 
0

Sorry, reposted

 Jan 30, 2016
edited by SpawnofAngel  Jan 30, 2016

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