if sin theta equals 3/7, what is tan theta?

2 answers

sinA = 3/7 = Y/r.

x^2 + y^2 = r^2
x^2 + 3^2 = 7^2.
x^2 = 7^2 - 3^2 = 40.
X = sqrt(4*10) = 2*sqrt10.

tanA=Y/X = 3 / 2*sqrt10 = 3*sqrt10/20.

NOTE: The radical was removed from the
denominator by multiplying numerator and denominator by sqrt10.
sin theta = o/h
that leaves adjacent side open
a^2 + b^2 = c^2
3^2 + b^2 = 7^2
9 + b^2 = 49
b^2 = 40
b = srt 40 adj side now equals sqrt 40
tan theta = o/a = 3/sqrt 40 =
3 * sqrt 40/40