The light from a lamp casts a shadow of a man standing 10 feet away from the lamppost. The shadow is 7 feet long. The angle of elevation from the tip of the shadow to the lamp is 50 degrees. To the nearest foot, the lamppost is _____ feet tall.

Question

zab505 · Answer

@amistre64

amistre64 · Answer

any ideas to start with?

zab505 · Answer

I forgot how to do the equation

amistre64 · Answer

its just trig .... drawing a picture is useful for the most part, helps us organize the data

amistre64 · Answer

|dw:1405970825872:dw|

amistre64 · Answer

now to find the hieght of the lamppost, what trig function do yo think we might be able to use?  any idea?

zab505 · Answer

Something like cos tan not sure

amistre64 · Answer

something like those yes,

since we have 2 legs and no hypotenuse to deal with, tangent works best

tan(A) = over/next.to

tan(50) = height/(10+7)

can you determine the height now?

zab505 · Answer

is that how the equation would go?

amistre64 · Answer

that how i would write it yes.

zab505 · Answer

Oh would it be 20 ft or 20.25 ft or how do they want the answer?

amistre64 · Answer

i dont know how they want the answer.  but whatever 17 tan(50) gets us is it

amistre64 · Answer

to the nearest foot, so either 20 or 21 ....

amistre64 · Answer

i dont know if nearest means round, or something else

amistre64 · Answer

my bet is on 20 tho

zab505 · Answer

Thank you so much!

amistre64 · Answer

youre welcome