Q. In △DEF,e=840 inches, d=760 inches and ∠D=134∘. Find all possible values of ∠E, to the nearest degree.Answer:
Apply Law of Sines: To find the possible values of /_E, we can use the Law of Sines, which states that the ratio of the length of a side of a triangle to the sine of the opposite angle is the same for all three sides of the triangle. The formula is:sin(A)a=sin(B)b=sin(C)cwhere a, b, and c are the lengths of the sides, and A, B, and C are the opposite angles. In this case, we have side e and angle D, so we can set up the ratio for side e and angle E.
Find Sine of Angle D: First, we need to find the sine of angle D. Since /_D is 134 degrees, we can calculate:sin(D)=sin(134∘)Using a calculator, we find that:sin(134∘)≈0.656059
Set Up Ratio for Side e: Now, we can set up the Law of Sines ratio for side e and angle E:sin(E)e=sin(D)dSubstituting the known values, we get:sin(E)840=0.656059760
Solve for Sin(E): Solving for sin(E), we have:sin(E)=0.656059760840sin(E)=760840×0.656059sin(E)≈760551.08956sin(E)≈0.725118
Calculate Angle E: To find angle E, we take the inverse sine (arcsin) of 0.725118:E=arcsin(0.725118)Using a calculator, we find that:E≈46.57∘Since we need to round to the nearest degree, /_E is approximately 47 degrees.
Calculate Angle E: To find angle E, we take the inverse sine (arcsin) of 0.725118:E=arcsin(0.725118)Using a calculator, we find that:E≈46.57∘Since we need to round to the nearest degree, /_E is approximately 47 degrees.However, we must consider that there could be another possible value for angle E because the sine function is positive in both the first and second quadrants. Since the sum of angles in a triangle must be 180 degrees, we can find the other possible value for angle E by subtracting angle D and our found angle E from 180 degrees:180∘−134∘−47∘=−1∘This result is not possible because angles in a triangle cannot be negative. Therefore, there is only one possible value for angle E.
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