Expert: Paul Klarreich - 3/11/2009

Question
Laura Bernett is 5 ft-4 inches tall. She stands 14 feet from a streetlight and casts a 10-foot-long shadow. How tall is the streetlight? What is angle θ? (Round your answers to two decimal places.)

the pole is to the left and she is to the right of it.. the angle is the smaller triangle of her and the end of her shadow... so its the bottom right of the whole large triangle... (as from the picture)

i put feet into inches and try to do tan 64/48 to get the angle but i keep getting 1 point something and that's anywhere near degrees.. i don't know what i'm doing wrong... could you run me through the steps and formulas to use.  

Answer
Questioner:   ray
Category:  Calculus
Private:  No
 
Subject:  hi
Question:  Laura Bernett is 5 ft-4 inches tall. She stands 14 feet from a streetlight and casts a 10-foot-long shadow. How tall is the streetlight? What is angle θ? (Round your answers to two decimal places.)

the pole is to the left and she is to the right of it.. the angle is the smaller triangle of her and the end of her shadow... so its the bottom right of the whole large triangle... (as from the picture)

i put feet into inches and try to do tan 64/48 to get the angle but i keep getting 1 point something and that's anywhere near degrees.. i don't know what i'm doing wrong... could you run me through the steps and formulas to use.

......................................
Your angle 't' should solve this equation:
       64 (inches)
tan t = -----------
       120 (inches)

The steps are (using the Windows Calc):
(make sure degrees is checked)
64
/
120
=
INV
tan
---- that's it.

After that, use tangent again to find the height of the light.