How do I find the angle of AHC?

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1 Answer
Apr 16, 2018

#angle H=74.4# degrees

Explanation:

Not sure if I'm approaching this correctly, but it looks to me like you could make this into some right triangles: #DeltaHDA#, #DeltaHGC#, and #DeltaABC#.
In triangle #DeltaHDA#, you are looking for #HA# given #HD=3#, #DA=4#, and #angleD# is right, so using the Pythagorean Theorem: #(HD)^2+(DA)^2=(HA)^2#
#(HA)^2=25#
#(HA)=5#
Using the same process for the other triangles I mentioned (if you need me to expand it feel free to ask), #HC=6.708...# and #AC=7.211...#.

Therefore, you can use the Law of Cosines to find #angleH#:
#theta=cos^-1((a^2+b^2﹣c^2)/(2ab))# Substituting Values:
#angle H =cos^-1(((HA)^2+(HC)^2﹣(AC)^2)/(2(HA)(HC)))# Which simplifies to
#angle H=~74.44# (in degrees), rounded to the nearest tenth is
#angle H=74.4#