Trigonometry help, measuring the earth!?
Trigonometry help, measuring the earth!?
Angle
A= 87.77 degrees
B=90
C=2.23
Side length
AC= 3 miles + r
CB=r
BA=m
I need to solve for r, I used a method that makes sense to me but doesn't give the correct answer. I want to know why it is wrong.
sin(2.23)=m/(3+r)=cos(87.77) using co function theorem thus
3sin(2.23)+rsin(2.23)=m=3cos(87.77)+rco... Implies
3sin(2.23)+rsin(2.23)=3cos(87.77)+rcos(... using this rule; (a=b=c thus a=c)
3sin(2.23)+rsin(2.23)=3cos(87.77)+rcos(...
3sin(2.23)-3cos(87.77)=rcos(87.77)-rsin...
3sin(2.23)-3cos(87.77)=r(cos(87.77)-sin...
(3sin(2.23)-3cos(87.77))/(cos(87.77)-si...
Thus I should have solved r but the value I get is completely wrong.
r apparently equals -4.8*10^13miles
I know you can simply take cos(2.23)= r/3+r which implies
(3cos(2.23))/(1-cos(2.23))=r
r=3958miles
I just don't understand why the other approach doesn't work.
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