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Tagged: Cos Rule, Non-Right Trig, trigonometry
In the given ΔPQR, find the angle θ to the nearest degree.
Remember that the side opposite the angle you are looking for is the side that goes into the ‘minus’ and is not on the bottom
\cos\theta=\frac{2.5^2+3^2-4.2^2}{2\times2.5\times3} θ = 99°
\cos\theta=\frac{2.5^2+3^2-4.2^2}{2\times2.5\times3}