Q. In ΔUVW,w=5.3cm,v=4.8cm and ∠V=151∘. Find all possible values of ∠W, to the nearest 10th of a degree.Answer:
Use Law of Sines: Use the Law of Sines to find the ratio of the sides to the sines of their opposite angles.sinWw=sinVvSubstitute the given values into the equation.sinW5.3=sin151∘4.8
Calculate sine of V: Calculate the sine of angle V.sin151∘≈0.5150
Substitute and solve: Substitute the value of sin V into the equation and solve for sin W.sinW5.3=0.51504.8sinW=4.85.3×0.5150sinW≈4.82.7295sinW≈0.5686
Find possible values of W: Find the possible values of angle W using the inverse sine function.W≈sin−1(0.5686)Since the sine function has a range of [−1, 1] and is positive in the first and second quadrants, there are two possible angles for W: one acute and one obtuse.W1≈sin−1(0.5686)W2≈180∘−W1
Calculate first W: Calculate the first possible value of angle W.W1≈sin−1(0.5686)W1≈34.7∘
Calculate second W: Calculate the second possible value of angle W.W2≈180∘−34.7∘W2≈145.3∘
Check triangle angles: Check if the sum of angles in the triangle exceeds 180 degrees when using the second possible value of angle W.
151^\circ + 145.3^\circ > 180^\circ
This is not possible in a triangle, so the only valid solution for angle W is the acute angle.
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